Statistics Questions and Answers

In a study the data you collect is Mood on a Happy OK Sad scale This data is Quantitative Qualitative Categorical

A political scientist surveys 33 of the current 99 representatives in a state s congress What is the size of the sample What is the size of the population

customers waited for their orders at two different restaurants There were 19 wait times recorded for the first restaurant and 16 recorded for the second Use the display to answer the questions that follow Number of minutes customers waited First restaurant Second restaurant 807 9821101013444 97665500 2 33999 6651 3 3578 Key 8 8 0 7 7 a What were the ranges of wait times for the two restaurants First restaurant Second restaurant b Which restaurant had the greater median wait time OFirst restaurant Second restaurant The medians were the same c Which restaurant had more wait times from 10 to 19 minutes OFirst restaurant OSecond restaurant OEach had the same X

The high temperatures in degrees Fahrenheit of a random sample of 6 small towns are 99 5 98 1 96 9 98 9 96 4 99 6 Assume high temperatures are normally distributed Based on this data find the 90 confidence interval of the mean high temperature of towns Enter your answer as an open interval i e parentheses accurate to two decimal places because the sample data are reported accurate to one decimal place 90 C I Answer should be obtained without any preliminary rounding However the critical value may be rounded to 3 decimal places

K Suppose a researcher wants to conduct research to determine it car rental company X is more expensive than car rental company Y to rent a mid size car for a weekend To do this he randomly selects six locations where both car rentals are located and determines the re cost as shown in the table Location X Y A 493 450 Suppose the researcher computes the difference as difference X Y Based on this determine the null and alternative hypotheses T Y B 185 182 C 322 322 Ho H Y Type integers or decimals Do not round D 398 390 E 305 350 F 350 350

Find an invertible matrix P and a diagonal matrix D such that P AP D 2 12 9 27 0 2 3 9 0 9 0 2 A P 1 0 1 1 0000 0 0 0 0 0 0 0 0 0 0 0 0 D 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

A certain manufacturer makes 400W light bulbs Assume that these light bulbs have lifetimes that are normally distributed with a mean lifetime of 410 hours and a standard deviation of 52 hours Use this table or the ALEKS calculator to find the percentage of light bulbs with lifetimes shorter than 371 hours For your intermediate computations use four or more decimal places Give your final answer to two decimal places for example 98 23

A simple random sample of 62 colleges and universities in the United State had a mean tuition of 18 974 with a standard deviation of 9 640 a Construct a 89 confidence interval for the mean tuition for all colleges and universities in the United States Please round the answers to 3 decimal places Critical value z or t Margin of Error E Confidence Interval Enter the positive one b Interpret your result in part a in a complete sentence

A college offers a self paced course in algebra College officials are interested in the number of hours it takes students to meet the objectives of the course In a sample of 39 students the mean number of hours was 75 9 with a standard deviation of 54 3 Round all answers to THREE decimal places a Construct a 94 confidence interval for the mean number of hours it takes for a student to meet the course objectives Critical value z or t Margin of Error E Confidence Interval Enter the positive one b Interpret your result in part a in a complete sentence

Find the sample size necessary to estimate the mean arrival delay time for all American Airlines flights from Dallas to Sacramento to within 5 minutes with 95 confidence Based on a previous study arrival delay times have a standard deviation of 38 1 minutes

SAT scores are normally distributed with a mean of 1 500 and a standard deviation of 300 An administrator at a college is interested in estimating the average SAT score of first year students If the administrator would like to limit the margin of error of the 84 confidence interval to 20 points how many students should the administrator sample Make sure to give a whole number answer

Estimate the population mean by finding a 95 confidence interval given a sample of size 279 with a mean of 31 9 and a standard deviation of 17 8 Preliminary a Is n 30 Yes No b Confidence Interval What is the 95 confidence interval to estimate the population mean Enter the tri linear inequality values accurate to one decimal place

Assuming the population has an approximate normal distribution if a sample size n 16 has a sample mean 38 with a sample standard deviation s 4 find the margin of error at a 99 confidence level Round the answer to two decimal places

al Arts Il Mode Livome IESSIOUZ 3 4 Homework Ruth wishes to install an irrigation system to water her five flo between her gardens are shown in the figure to the right Use through c a Represent the given information with a weighted graph Ch OA R 65 128 30 41 M 29 45 I J 74 GETLE 43 H OB R 30 I

1 3 Homework K Kristin has to pick up her children who all atter School S Kristin estimates the distance amor parts a through c below al Represent this traveling salesman problem

mework Kristin Wilson lives in Cha she visit each of these citi

3 3 Homework K Erik Allen repairs photocopy r O A 7

The primary concern for performing a hypothesis test to compare the means and of two populations is deciding whether the mean of Population 1 is greater than the mean of Population 2 a Determine the null and alternative hypotheses Note Always place the mean of Population 1 on the left b Classify the hypothesis test as two tailed left tailed or right tailed a Complete the hypotheses Ho P H H b This hypothesis test is H H tailed HEKECH

Classify the two given samples as independent or dependent Sample 1 Sample 2 The number of hours 41 kids spend playing video games in a week The number of hours 48 adults spend playing video games in a week Choose the correct answer below A The two given samples are dependent because the same people were sampled OB The two given samples are independent because the same people were sampled OC The two given samples are dependent because different people were sampled D The two given samples are independent because different people were sampled

According to a recent survey the salaries of entry level positions at a large company have a mean of 41 750 and a standard deviation of 8000 Assuming that the salaries of these entry level positions are normally distributed find the proportion of employees in entry level positions at the company who earn at least 53 000 Round your answer to at least four decimal places

Suppose that the time required to complete a 1040R tax form is normal distributed with a mean of 90 minutes and a standard deviation of 20 minutes What proportion of 1040R tax forms will be completed in at least 120 minutes Round your answer to at least four decimal places

Here are three histograms Histogram A 36 32 28 24 20 16 12 8 4 0 0 3 6 9 12 15 18 21 24 27 30 33 36 32 28 24 20 16 12 Hictogram 4 Histogram B 0 3 6 9 12 15 18 21 24 27 30 33 a Which histogram is the closest to being symmetric OHistogram A OHistogram B OHistogram C b Which histogram is best described as bimodal OHistogram A OHistogram B O Histogram C c Which histogram is the closest to being bell shaped OHistogram B OHistogram C OHistogram A d Which histogram is skewed to the left the most Histogram R Histogram C 36 32 28 24 20 16 12 8 4 0 Histogram C hrb 0 3 6 9 12 15 18 21 24 27 30 33 X 3

Question 2 25 points What is the critical value z associated with a 95 confidence interval Criscal Value z score O 0 950 O 1 645 1 960 2 575 95 Critical Value z score

Section 8 3 26 Confidence Intervals for a Population Mean Standard Deviation Known Contaminated water In a sample of 42 water specimens taken from a construction site 26 contained detectable levels of lead a Construct a 90 confidence interval for the proportion of water specimens that contain detectable levels of lead b Construct a 95 confidence interval for the proportion of water specimens that contain detectable levels of lead c What is the effect of increasing the level of confidence on the width of the interval

Compute the least squares X y 5 7 1 9 regression line for the given data set 6 5 5 8 4 9 1 2 1 7 3 0 4 1 6 2 4 4 4 8 0 8 3 9

3 points A number of students were surveyed about how many hours a week they study The results are shown in the set below 0 5 0 0 5 0 1 1 2 1 1 0 10 The mean of these data is type your answer The median of these data is type your answer The mode of these data is type your answer Round to nearest tenth 1 point A number of students were surveyed about how many hours a week they study The results are shown in the set below 0 5 0 0 5 0 1 1 2 1 1 0 10 In statistics an outlier valor at pico is a data point that is far and away from the rest of the data it is especially far from the mean or median and feels out rest of the data With this definition in mind an outlier in this data set could be type your answer 1 point Suppose that your test scores in your math class were as follows 8 8 9 8 5 9 10 You want to get an A average at least 9 10 and have one more test Is it possible to have at least a 9 average for your test scores The maximum amount of points available on a test in this context is 10 points This is very important esta info es muy importante Yes because with a score of 10 5 the sum of all scores will be 63 just enough to make a 9 average on the tests Yes because with a score of 10 the average will be at least 9 No because the score necessary to make a 9 average is 10 5 a number greater than the maximum points possible on the last test No because the chances of making a 10 10 on the last test are slim to none Math is hard

1 a b c d c State of Nature 1 2 2 a 24 b 16 3 a b C d e c 9 2 d 4 9 c 84 4 a b The mean rate of return on security A is 8 9 10 11 12 C d c The standard deviation in return on B is Probability TOT 0 7 0 3 The covariance in the rates of return is 48 48 84 84 none of the above The correlation coefficient is 1 0 5 0 5 none of the above Rate of Return on A 15 5 Rate of Return on E 0 20

Est Length 2 00 00 Page 1 1 4 2 5 3 Quiz Neftali Moreno Miranda Attempt 1 UCLWCCII J anu 7 J between 55 and 70 Question 3 20 points If a set of data is normally distributed wh less than 1 30

Question 1 14 3 points Given that a data set has a Median of 5 and an Inner Quartile Range of 3 what is the possible range of values that could be the Lower Quartile Q for the data set It may help to create or think about a box and whisker plot O O O 2 Q 8 0 Q 2 2 Q 5 5 Q 8 Question 2 14 3 points Use the Box and Whisker Plot to identify the median H 5 7 13 17 24

Question 2 14 3 points Use the Box and Whisker Plot to identify the median 0 O 7 13 17 19 HC 5 7 10 13 17 20 24 Question 3 14 3 points Consider the following Ordered Data Set 5 22 23 30 34 34 39 40 41 48 Which line plot below best represents the data

Question 7 14 3 points Which histogram below best shows a data set that is symmetric normal O O Frequency Frequency Frequency 6 1 876543NN 87654321 1 2 3 4 5 6 7 8 9 10 Data Value 1 2 3 4 5 6 7 8 9 10 Data Value

Use the following graph to answer the next three questions Find the rate of change in the number of new employees at the plant for each month inter below Round your answers to the nearest tenth Number 140 130 120 110 100 90 10 80 70 60 20 50 40 30 Jan Feb Mar 16 From February to May Apr May new employees per month Months Aug Sep Oct Nov Dec

A parenting magazine reports that the average amount of wireless data used by project Ella sets out to prove the magazine wrong She claims that the mean am collects information from a simple random sample of 4 teenagers at her high sch standard deviation of 0 7 Gb per month Assume that the population distributio level of significance Step 3 of 3 Draw a conclusion and interpret the decision Answer We fail to reject the null hypothesis and conclude that there is s that the average amount of wireless data used by teenagers ead We reject the null hypothesis and conclude that there is sufficie

A parenting magazine report project Ella sets out to prove collects information from a s standard deviation of 0 7 GH

A children s clothing company sells hand smocked dresses for girls The length of one pa The company regularly tests the lengths of the garments to ensure quality control and or shorter than 28 inches the machines must be adjusted The most recent simple rand 29 15 inches with a standard deviation of 2 61 inches Assume that the population distr hypothesis test on the accuracy of the machines at the 0 10 level of significance Step 3 of 3 Draw a conclusion and interpret the decision Answer We reject the null hypothesis and conclude that there is sufficient evid O mean length of the particular size of dress is found to be significantly l machines must be adjusted We fail to reject the null hypothesis and conclude that there is sufficien O that the mean length of the particular size of dress is found to be signi and the machines must be adjusted

rently takes users a mean of 11 minutes to install the most popular computer prog any After changes have been made to the program the company executives want nes so that they can change their advertising accordingly A simple random sample for them to install the software The sample mean is 10 7 minutes with a standard at the 0 10 level of significance to see if the mean installation time has changed p 3 of 3 Draw a conclusion and interpret the decision swer We reject the null hypothesis and conclude that there is sufficient evid D new mean installation time is different from 11 minutes and that Rode advertising We fail to reject the null hypothesis and conclude that there is sufficien O that the new mean installation time is different from 11 minutes and th advertising

3 A teacher drew a line segment that was 20 in lon of her students to estimate the length of the seg to construct this dot plot 17 18 19 20 Estimate length in 21

a Translate the argument into symbolic form b Use a truth table to determine whether the argument is valid or invalid Ignore differences in past present and future tense If you re bad Santa will give you coal Santa didn t give you coal You weren t bad a Let p be You re bad and let q be Santa gives you coal What is the argument in symbolic form OA p q q P OC p q P q OB pq q p OD p q 9 p b is the given argument valid or invalid OA The argument is invalid because its corresponding statement is an implication OB The argument is valid because its corresponding statement is a tautology OC The argument is invalid because its corresponding statement is a tautology O D The argument is valid because its corresponding statement is not an implication

The lengths of movie files that are available for streaming are modeled using the normal distribution shown below The mean of the distribution is 189 7 min and the standard deviation is 20 2 min In the figure V is a number along the axis and is under the highest part of the curve And U and W are numbers along the axis that are each the same distance away from V Use the empirical rule to choose the best value for the percentage of the area under the curve that is shaded and find the values of U V and W 120 U 140 Percentage of total area shaded Choose one 160 180 200 V Time in min 220 240 W 260 X

The scores on a standardized test for a certain year are modeled using the normal distribution shown below The mean of the distribution is 72 4 points and the standard deviation is 5 5 points In the figure V is a number along the axis and is under the highest part of the curve And U and W are numbers along the axis that are each the same distance away from V Use the empirical rule to choose the best value for the percentage of the area under the curve that is shaded and find the values of U V and W 55 60 Percentage of total area shaded Choose one 65 U O 70 Test score 75 W 80 85 90 X S

Which transformation would take Figure A to Figure B A 10 9 8 7 6 5 4 3 2 1 y 10 9 8 7 6 5 4 3 2 1 1 2 3 4 5 6 7 8 9 10 1 2 3 4 5 6 7 8 9 10 M B X A clockwise rotation of 90 about the origi O A clockwise rotation of 180 about the orig O A reflection over the line y x O A reflection over the line y x

stion 14 examining a time plot we quency

3371 quizzes 264393 take on 10 hat has a right skew es that there are more data points with sma

Find the area of the shaded region under the standard normal curve If convenient use technology to find the area 3 21

Find the indicated area under the standard normal curve To the left of z 0 35 Click here to view page 1 of the standard normal table Click here to view page 2 of the standard normal table The area to the left of z 0 35 under the standard normal curve is Round to four decimal places as needed

Find the z score that cuts off the bottom 34 of the distribution

on 6 omes in a graph representing cat ways be displayed in the order they y be sorted in increasing order

estion 9 ch of the following are correct notations for th The standard deviation of a sample of observations is leviation of an entire population is labeled with the C The standard deviation of a sample of observations an oth labeled with the Greek letter SIGMA

uestion 11 ercentile is is a numerical summary for categoric common label on the vertical axis

3371 quizzes 264393 take on 8 f the following are correct notations for the m ean of a quantitative variable is always labeled with ample of observations or an entire population