Statistics Questions and Answers

Find the critical value ze necessary to form a confidence interval at the level of confidence shown below. c=0.86 Zc =

Find the critical value(s) and rejection region(s) for the indicated t-test, level of significance a, and sample size n. Two-tailed test, a=0.02, n=17

Find the minimum sample size n needed to estimate µ for the given values of c, σ, and E. c=0.95, σ=6.4, and E= 2 Assume that a preliminary sample has at least 30 members.

The following data represent the flight time (in minutes) of a random sample of seven flights from one city to another city. 284, 270, 260, 266, 257, 263, 269 Compute the range and sample standard deviation of flight time.

A factory machine is producing Jeans to the length of 49cm. The standard deviation of the population is taken to be 0.3cm. A sample of 50 pairs of jeans is taken and is found to have a mean length of 48cm. Based on a 95% Confidence level interval, should the machine be checked and adjusted? [5]

Use the calculator displays to the right to make a decision to reject or fail to reject the null hypothesis at a significance level of a = 0.01 Choose the correct answer below. A. Since the P-value is greater than a, reject the null hypothesis. B. Since the P-value is less than a, fail to reject the null hypothesis. C. Since the P-value is greater than a, fail to reject the null hypothesis. D. Since the P-value is less than a, reject the null hypothesis.

Your medical research team is investigating the standard deviation of the cost of a 30-day supply of a certain heart medication. A pharmaceutical company thinks that the standard deviation of the cost is more than $23. You want to support this claim. How would you write the null and alternative hypotheses?

A researcher studies children in elementary school and finds a strong positive linear asso- ciation between height and reading scores. a) Does this mean that taller children are generally better readers? b) What might explain the strong correlation?

In a poll, 1,005 adults in a country were asked whether they favor or oppose the use of "federal tax dollars to fund medical research using stem cells obtained from human embryos." Among the respondents, 47% said that they were in favor. Identify the population and the sample. What is the population in the given problem? Choose the correct answer below. A. All adults in the country B. 47% of the 1,005 adults selected C. 47% of all adults in the country D. The 1,005 adults selected Identify the sample for the given problem. Choose the correct answer below. A. 47% of the 1,005 adults selected B. The 1,005 adults selected C. 47% of all adults in the country. D. All adults in the country

A small warehouse employs a supervisor at $1200 a week, an inventory manager at $700 a week, six stock boys at $400 a week, and four drivers at $500 a week. a) Find the mean and median wage. b) How many employees earn more than the mean wage? c) Which measure of center best describes a typical wage at this company: the mean or the median? d) Which measure of spread would best describe the payroll: the range, the IQR, or the standard deviation? Why?

For the statement below, write the claim as a mathematical statement. State the null and alternative hypotheses and identify which represents the claim. A laptop manufacturer claims that the mean life of the battery for a certain model of laptop is more than 6 hours. Identify which is the claim. A. The alternative hypothesis Ha: μ< 6 is the claim B. The alternative hypothesis Ha: > 6 is the claim. C. The null hypothesis Ho: μ = 6 is the claim D. The null hypothesis Ho: u≥6 is the claim E. The null hypothesis Ho: u≤6 is the claim.

A pharmaceutical company wants to test the effectiveness of a new allergy drug. The company identifies 250 females 30-35 years old who suffer from severe allergies. The subjects are randomly assigned into two groups. One group is given the new allergy drug and the other is given a placebo that looks exactly like the new allergy drug. After six months, the subjects' symptoms are studied and compared. Answer parts (a) through (c) below. (a) Identify the experimental units and treatments used in this experiment. Choose the correct answer below. A. The experimental unit is the new allergy drug. The treatments are the severe allergies the patients suffer from. B. The experimental units are the 30- to 35-year-old females being given the treatment. The treatment is the new allergy drug. C. The experimental units are the 30- to 35-year-old females being given the treatment. The treatment is six months. D. The experimental units are the symptoms from the drug. The treatment is the new allergy drug.

True or false If false, explain briefly. a) We choose the linear model that passes through the most data points on the scatterplot. b) The residuals are the observed y-values minus the y-values predicted by the linear model. c) Least squares means that the square of the largest residual is as small as it could possibly be.

Determine whether the underlined number describes a population parameter or a sample statistic. Explain your reasoning. A survey of 2213 adults in a country found that 85% think that militant terrorists are a major threat to the well-being of their country. Choose the correct statement below. A. The number is a population parameter because it is a numerical description of all of the people in the country. B. The number is a sample statistic because it is a numerical description of all of the people in the country. C. The number is a population parameter because it describes the people in a sample, which is a subset of all of the people in the country. D. The number is a sample statistic because it describes the people in a sample, which is a subset of all of the people in the country.

A local chess club claims that the length of time to play a game has a mean of 27 minutes or more. Write sentences describing type I and type II errors for a hypothesis test of this claim. A type I error will occur if the actual mean of the length of time to play a game is 27 minutes, but you the null hypothesis, A type II error will occur if the actual mean of the length of time to play a game is 27 minutes, but you the null hypothesis,

Choose the correct description of the population. A. The party of registered voters in the county B. The number of registered voters in the county who responded to a survey C. The number of registered voters in the county D. The party of registered voters in the county who responded to a survey

A sample of students is selected and it is found that 50% own a television. Choose the correct statement below. Parameter because the value is a numerical measurement describing a characteristic of a population. Statistic because the value is a numerical measurement describing a characteristic of a population. Statistic because the value is a numerical measurement describing a characteristic of a sample. Parameter because the value is a numerical measurement describing a characteristic of a sample.

Define and distinguish among mean, median, and mode. Choose the correct description of the mean below. A. The mean is the middle value in a data set. It is not affected by outliers. B. The mean is the middle value in a data set. It can be strongly affected by outliers. C. The mean is the most common value in a data set. It is not affected by outliers. D. The mean is the most common value in a data set. It can be strongly affected by outliers. E. The mean is the sum of all the values divided by the number of values. It is not affected by outliers. F. The mean is the sum of all the values divided by the number of values. It can be strongly affected by outliers. Choose the correct description of the median below. A. The median is the middle value in a data set. It is not affected by outliers. B. The median is the middle value in a data set. It can be strongly affected by outliers. C. The median is the sum of all the values divided by the number of values. It is not affected by outliers. D. The median is the sum of all the values divided by the number of values. It can be strongly affected by outliers. E. The median is the most common value in a data set. It can be strongly affected by outliers.

The numbers of words defined on randomly selected pages from a dictionary are shown below. Find the mean, median, and mode of the listed numbers. 69 33 50 49 66 59 52 63 79 31 What is the mean? Select the correct choice below and, if necessary, fill in the answer box within your choice. A. The mean is (Round to one decimal place as needed.) B. There is no mean. What is the median? Select the correct choice below and, if necessary, fill in the answer box within your choice. A. The median is (Round to one decimal place as needed.) B. There is no median. What is (are) the mode(s)? Select the correct choice below and, if necessary, fill in the answer box within your choice. A. The mode(s) is (are) (Round to one decimal place as needed. Use a comma to separate answers as needed.) B. There is no mode.

For any set of data, what must be done to the data before percentiles can be determined? Choose the correct answer below. A. The data must be ranked. B. The quartiles of the data set must be found. C. The frequency of each piece of data must be found. D. The data must be summed.

For the following set of numbers, find the mean, median, mode and midrange. 11, 11, 12, 13, 15, 15, 15, 16, 27 The mean is The median is Select the correct choice below and fill in any answer boxes within your choice. A. The mode is (Use a comma to separate answers as needed.) B. There is no mode. The midrange is

By studying the standard deviation formula, given below, explain why the standard deviation of a set of data will always be greater than or equal to 0. s=√Σ(x-x)² n-1 Choose the correct answer below. A. The values of (x-x)2 will always be greater than or equal to 0. B. The mean, x, will always be greater than or equal to 0. C. The values of x will always be greater than or equal to 0. D. The values of x-x will always be greater than or equal to 0.

If you compared the distribution of weights of 20 elite female gymnasts to the distribution of weights of 20 randomly selected women, you would expect the variation of the weights to be greater for the gymnasts, greater for the randomly selected women, or the same for both groups? Choose the correct answer below. A. The variation of the weights should be greater for the gymnasts. Because female gymnasts tend to be petite and train hard, their weights are all very different. This is not the case for the female population as a whole, whose weights are all very similar. B. The variation of the weights should be greater for the gymnasts. Because there are a greater number of female gymnasts than there are women in the female population as a whole, the variation in weights will necessarily be greater as well. C. The variation of the weights should be the same for both groups. No two women are alike, and this holds for female gymnasts as well as for the female population as a whole. D. The variation of the weights should be greater for the randomly selected women. Because female gymnasts tend to be petite and train so hard, their weights are all very similar. This is not the case for the female population as a whole, whose weights are all very different. E. The variation of the weights should be greater for the randomly selected women. Because there are a greater number of women in the female population as a whole than there are female gymnasts, the variation in weights will necessarily be greater as well.

The salaries of 10 employees of a small company are listed. Complete parts (a) through (f) below. a) Determine the mean. The mean salary is $ 37100. (Simplify your answer.) b) Determine the median

Determine the mean, median, mode, and midrange of the set of data. 1, 9, 10, 26, 36, 15, 11, 8, 1

The prices of the 19 top-rated all-season tires for a specific tire size, are as follows. Answer parts (a) - (c). $87 $115 $98 $79 $81 $92 $94 $88 $94 $80 $108 $113 $101 $96 $86 $92 $76 $99 $91 a) Determine Q₂. Q₂ =

Coke wants to survey people at the Indiana State Fair and try and decide if they like Diet Coke or Diet Pepsi better. Coke hires the employees and supplies all the soda. Is the collection of this data biased? Biased Non-biased

Find the range and standard deviation of the set of data. 6, 10, 11, 13, 14, 18 The range is 12. (Simplify your answer.) The standard deviation is (Round the final answer to the nearest hundredth as needed. Round all intermediate values to the nearest hundredth as needed.)

Identify the sampling technique used to obtain the following sample. A state is divided into regions using zip codes. A random sample of 40 zip code areas is selected. Choose the correct sampling technique below. A. Convenience sampling B. Systematic sampling C. Cluster sampling D. Stratified sampling E. Random sampling

You have the following question on a survey. "Would you like a greasy hamburger that is microwaved for lunch or would you rather have a lean, healthy, grass fed grilled hamburger for lunch?" Biased Non-biased

Find the range and standard deviation of the set of data. 230, 235, 240, 245, 250, 255, 260 The range is 30. (Simplify your answer.) The standard deviation is

The following statistics represent weekly salaries at a construction company. Mean $800 First quartile $430 Median $690 Third quartile $765 Mode $680 83rd percentile $805 The most common salary is $ 680. The salary that half the employees' salaries surpass is $

Without actually doing the calculations, decide which, if either, of the following two sets of data will have the greater standard deviation. Explain why. 5,8,9,10,12,16 12,13,13,14,14,15 Choose the correct answer below. A. The standard deviations would be the same since the spread of data about each mean is the same. B. The first set will have the greater standard deviation because the data have a smaller spread about the mean. C. The second set will have the greater standard deviation because the data have a greater spread about the mean. D. The first set will have the greater standard deviation because the data have a greater spread about the mean.

Classify this question: "Are you willing to deal with the noise and increased traffic just to have another unnecessary store like IKEA built in Indianapolis?" Biased Unbiased

McDonalds wanted to find out the favorite sandwich of teen-agers from the ages of 15 - 18. They release a questionnaire to 3 local high schools and ask them to respond with whether or not they liked the Big Mac, Fish Sandwich or Chicken. They calculated the results to decide which sandwich to market to the area. Experimental None of the answer choices Survey Observational Study

You want to estimate the number of students in a high school who ride the bus. Which sample is best? 7 random students in the hallway 50 students in the band 100 students during the lunch period The football team

You want to know what freshman think of their science class. You poll 100 freshman by using a random number generator to pick students by their student number. Random Non-random

The mean height of women in a country (ages 20-29) is 64.2 inches. A random sample of 65 women in this age group is selected. What is the probability that the mean height for the sample is greater than 65 inches? Assume σ = 2.96.

You survey customers at a mall. You want to know which stores they shop at the most. You walk around a computer shop and choose 20 customers there for your survey. Non-random Random

The population mean and standard deviation are given below. Find the required probability and determine whether the given sample mean would be considered unusual. For a sample of n = 70, find the probability of a sample mean being less than 22.1 if u = 22 and σ = 1.31. For a sample of n = 70, the probability of a sample mean being less than 22.1 if µ = 22 and σ=1.31 is ___ (Round to four decimal places as needed.). Would the given sample mean be considered unusual? The sample mean___be considered unusual because it has a probability that is than 5%.

The amount of money Stephanie collected in tips in each of seven days is $46, $82, $103, $27, $54, $71, and $65. Determine the mean, median, mode, and midrange.

Find the probability and interpret the results. If convenient, use technology to find the probability. The population mean annual salary for environmental compliance specialists is about $62,000. A random sample of 36 specialists is drawn from this population. What is the probability that the mean salary of the sample is less than $58,500? Assume σ = $6,500. The probability that the mean salary of the sample is less than $58,500 is 0.00062. (Round to four decimal places as needed.) Interpret the results. Choose the correct answer below. A. About 0.06% of samples of 36 specialists will have a mean salary less than $58,500. This is not an unusual event. B. Only 6% of samples of 36 specialists will have a mean salary less than $58,500. This is an extremely unusual event. C. Only 0.06% of samples of 36 specialists will have a mean salary less than $58,500. This is an extremely unusual event. D. About 6% of samples of 36 specialists will have a mean salary less than $58,500. This is not an unusual event.

What is a sample obtained by using chance methods? Every member of the population has an equal chance of being selected. biased none of the answer choices random systematic

Identify the study as observational, experimental, or neither. A professor finds that people who are overweight have higher cholesterol levels than those that are not overweight. experimental observational neither answer choice

Classify the following: A person's salary and the amount of money saved. No correlation Correlation that implies causation Correlation only

The mean height of women in a country (ages 20-29) is 63.9 inches. A random sample of 75 women in this age group is selected. What is the probability that the mean height for the sample is greater than 64 inches? Assume σ = 2.69. The probability that the mean height for the sample is greater than 64 inches is.

A superintendent of schools decided to look at the GPA of the two high schools in his district to decide which one should receive more funding. High School A's GPA was approximately 5% higher than High School B's. What type of statistical study did the superintendent use? None of the answer choices Survey Observational Study Experimental

Construct the confidence interval for the population mean μ. c= 0.98, x̄ = 5.1, σ=0.9, and n=46

One way people have tried to stop smoking is switch to electronic cigarettes. A group of 50 smokers were randomly chosen. 25 continued to smoke cigarettes and 25 were given electronic cigarettes to smoke. The white blood cell count was taken before and after 20 minutes of smoking for each group and compared. What type of statistical survey is this? experimental none of the answer choices survey observational

Use the central limit theorem to find the mean and standard error of the mean of the indicated sampling distribution. Then sketch a graph of the sampling distribution. The per capita consumption of red meat by people in a country in a recent year was normally distributed, with a mean of 101 pounds and a standard deviation of 39.4 pounds. Random samples of size 17 are drawn from this population and the mean of each sample is determined.