Statistics Questions and Answers

Suppose that a study of elementary school students reports that the mean age at which children begin reading is 5 5 years with a standard deviation of 1 0 years Step 1 of 2 If a sampling distribution is created using samples of the ages at which 46 children begin reading what would be the mean of the sampling distribution of sample means Round to two decimal places if necessary Answer Keypad Keyboard Shortcuts Tables

A study on the latest fad diet claimed that the amounts of weight lost by all people on this diet had a mean of 23 9 pounds and a standard deviation of 7 3 pounds Step 1 of 2 If a sampling distribution is created using samples of the amounts of weight lost by 58 people on this diet what would be the mean of the sampling distribution of sample means Round to two decimal places if necessary Answer Tables Keypa Keyboard Shortc

Find the standard deviation of the sampling distribution of sample means using the given information Round to one decimal place if necess W 42 and 0 n 25 Answer

ide if the statement is True or False swer A sampling distribution of sample means has a mean equal to the population mean p False True

The geyser Old Faithful in Yellowstone National Park alternates periods of eruption which typically last from 1 5 to 4 minutes with periods of dormancy which are considerably longer The following table presents the durations in minutes of 30 dormancy periods that occurred during a recent year 90 92 66 89 98 89 97 99 90 88 83 90 116 101 66 86 83 97 82 82 Part 0 2 71 Send data to Excel Part 1 of 2 91 00 99 82 96 91 61 97 92 59 a Construct a frequency distribution using a class width of 5 and using 55 as the lower class limit for the first class Dormancy Period Frequency

In a certain college 38 of the physics majors belong to ethnic minorities If 20 students are selected at random from the physics majors what is the probability that less than 7 belong to an ethnic minority 0 755 0 312 0 489 0 511

Using the information from the two previous problems would it be unusual if one of these students had 14 correct answers on the quiz Yes No

Is the binomial distribution appropriate for the following situation Ask 125 randomly selected U S citizens if they have ever visited London England X is the number that say yes Yes No

Write a statement explaining what the probability means in the previous problem

The Value Line Survey a service for common stock investors provides its subscribers with up to date evaluations of the prospects and risks associated with the purchase of a large number of stocks Each stock is ranked 1 highest to 5 lowest according to Value Line s estimate of the stock s potential for price appreciation during the next 12 months Suppose you plan to purchase stock in three electrical utility companies from among eight that possess rankings of 2 for price appreciation Unknown to you two of the companies will experience serious difficulties with their nuclear facilities during the coming year If you randomly select the three companies from among the eight what is the probability that you select one of the companies with prospective nuclear difficulties a 15 28 b 3 28 c 3 14 d 5 14 e 9 14

Harold and Maude plan to take a cruise that departs from Miami together but they live in separate cities Based on their itinerary to Miami Harold s chance of making it to the cruise is 87 whereas Maude s is 91 Assume that the event of Harold making it is independent of the event of Maude making it What is the probability that only Harold makes it to the cruise a 0 87 b 0 91 c 0 0117 d 0 0783 e 0 3983

O Macmillan Learning How old are women when they have their first child The table displays the distribution of the age of the mother for all firstborn children in the United States in 2017 Age Count Age Count 10 14 years 1 892 30 34 years 329 623 15 19 years 162 536 35 39 years 124 637 20 24 years 395 927 40 44 years 24 049 25 29 years 417 162 45 49 years 2 377 The number of firstborn children to mothers under 10 or over 50 years of age represent a negligible percentage of all first births and are not included in the table In which age classes do the median and quartiles fall Be sure to give all three values before checking your answer Q median Q3 45 49 years 35 39 years 30 34 years 10 14 years Answer Bank 20 24 years 30 34 years 40 44 years 15 19 years 25 29 years 35 39 years 45 49 years

A company manufactures batteries in batches of 24 and there is a 3 rate of defects Find the mean number of defects per batch O 23 28 O 0 744 O 0 696

Find the indicated probability A company purchases shipments of machine components and uses this acceptance sampling plan Randomiy select and test 20 components and accept the whole batch if there are fewer than 3 defectives If a particular shipment of thousands of components actually has a 8 rate of defects what is the probability that this whole shipment will be accepted O 0 5993 O 0 2711

ne problem The probability that a radish seed will germinate is 0 7 A gardener plants seeds in batches of 13 Find the standard deviation for the number of seeds germinating in each batch O 1 587 O 1 632

Use the given values of n and p to find the minimum usual value 2o and the maximum usual value u 20 1130 p 0 94 n O Minimum 1078 17 maximum 1046 23 O Minimum 1046 23 maximum 1078 17 O Minimum 1050 91 maximum 1073 49 O Minimum 1054 22 maximum 1070 18

Determine if the outcome is unusual Consider as unusual any result that differs from the mean by more than 2 standard deviations That is unusual values are either less than 20 or greater than 26 A survey for brand recognition is done and it is determined that 68 of consumers have heard of Dull Computer Company A survey of 800 randomly selected consumers is to be conducted For such groups of 800 would it be unusual to get 625 consumers who recognize the Dull Computer Company name O Yes O No

Find the indicated probability An airline estimates that 91 of people booked on their flights actually show up If the airline books 79 people on a flight for which the maximum number is 77 what is the probability that the number of people who show up will exceed the capacity of the plane O 0 0045 O 0 0051 O 0 0006

Find the mean of the given probability distribution The accompanying table shows the probability distribution for x the number that shows up when a loaded die is rolled Probability For a Loaded Die When Rolled O 3 50 O 0 17 O 4 01 O4 14 X 1 2 3 4 5 96 P x 0 11 0 13 0 13 0 14 0 12 0 37

Suppose that voting in municipal elections is being studied and that the accompanying table describes the probability distribution for four randomly selected people where x is the number that voted in the last election Is it unusual to find four voters among four randomly selected people Probability of Four People Voting XO234 1 P x 0 23 0 32 0 26 0 15 0 04

A company surveyed 32 male employees on their weight and the number of hours they were active every day The following scatterplot has a linear model and coefficient of determination Question 7 of 12 Weight in Pounds NO f x 9 6 x 205 54 0 76 200 190 180 170 160 150 140 130 120 Number of Hours Active Per Day 2018 WGU Powered by GeoGebra 12 Which statement about this regression is correct To answer the question of how many hours a man should be active to maintain a weight of 170 pounds use an interpolation and extrapolation value O To answer the question of how many hours a man should be active to maintain a weight of 170 pounds use an extrapolation value O To answer the question of how many hours a man should be active to maintain a weight of 170 pounds use the regression s coefficient of determination O To answer the question of how many hours a man should be active to maintain a weight of 179 pounds use an interpolation

Question 6 of 12 7 000 6 000 5 000 4 000 3 000 2000 1 000 0 Number of Gamers Per Day Which statement is true about this regression ng linear regression 0 96 f x 537 85x 801 42 Number of Days Since January 1 10 14 16 O 2018 WGU Powered by GeoGebra O By f 1 1 854 there was approximately 1 854 gamers on December 31 By f 15 6 600 there would be approximately 6 600 gamers on January 15 OA logistic regression should be used instead of a linear regression By the very good coefficient of determination a lin

A normal distribution has a standard deviation of 1 We want to verify a claim that the mean is greater than 12 A sample of 36 is taken with a sample mean of 12 5 Calculate the test statistic T S

We want to test whether the mean GPA of students in American colleges is different from 2 0 out of 4 0 The null and alternative hypotheses are 1 Ho 2 Ha 1 HO 2 Ha 2 0 2 0 Choose O Choose

Jeffrey as an eight year old established a mean time of 16 43 seconds for swimming the 25 yard freestyle with a standard deviation of 0 8 seconds His dad Frank thought that Jeffrey could swim the 25 yard freestyle faster using goggles Frank bought Jeffrey a new pair of expensive goggles and timed Jeffrey for 15 25 yard freestyle swims For the 15 swims Jeffrey s mean time was 16 seconds Frank thought that the goggles helped Jeffrey to swim faster than the 16 43 seconds Calculate the test statistic T S Use 2 decimal places

Question 4 of 12 30 25 20 451 Population in Thousands 10 f x 2 386 Which statement is true about this regression 0 72 Number of Years Since 1900 25 30 35 40 45 50 55 60 65 2018 WGU Powered by GeoGebra O Investigate the possible outlier before drawing any conclusion O By 65 22 2 on the function it can be estimated that the town s population was approximately 22 200 in 1965 This is an interpolation By 65 22 2 on the function it can be estimated that the town s population was approximately 22 200 in 1965 This is an extrapolation O A linear regression should be used before drawing any conclusion

1 Assume HO 9 and Ha u 9 2 Assume HO u s 6 and Ha 6 3 Your friend claims that his mean golf score is 63 4 You flip a coin and record whether it shows heads or tails You know the probability of getting heads is 50 but you think it is less for this particular coin 5 Your friend claims that his mean golf score is 63 You want to show that it is Choose O Choose Choose Choose Choose

Complete the table below by finding the equivalent values of the given value in the forms requested Simplify any fractions Proper Fraction or Mixed Number 1 4 A Decimal 0 04 Percent 45

Write as a decimal and as a percent as a decimal as a percent 1

Yoni returns to the doctor to get his stitches removed from his leg Before seeing his doctor the medical assistant takes his weight The scale reads 153 3 lbs Since the medical assistant is only required to write down a whole number for his weight what do they write down in his chart

Round 2 9998 to the nearest tenth

1 We ask each student in a large Social Psychology course to report how many hours they study Paul studies 12 hours per week corresponding to a standard score of 2 Anne has a standard score of 4 She spends only 3 hours each week on this course From this information determine the mean and variance for the whole class a Calculate Paul s and Anne s deviation scores b If the professor insists that every student in class must study 3 extra hours per week how would this change Paul s score deviation score and standard score

5 2 pts You want to determine if taking vitamins has an effect on the number of colds people get You ask subjects two questions 1 Do you regularly take vitamins and 2 How many colds have you had in the last six months You record and compare these results Is this an observation or an experiment

3 2 pts An online poll showed that 25 of Americans believe that public school principals should carry firearms Does this mean that roughly one quarter of Americans think this Explain your answer

2 2 pts You wish to determine the average number of siblings everyone in our Statistics class has Describe what process you would go through to collect a sample if you use a systematic sample

4 2 pts A researcher has group listen to classical music while studying The other group studies in silence Grades are measured at end of the trial Is this a blind experiment double blind experiment or neither

2 The following are the Test 1 scores of my Calculus 3 classes in the last 3 semesters 3 26 40 62 74 88 5 63 74 89 13 53 64 74 89 64 77 90 67 79 90 83 91 13 14 27 27 25 29 31 17 32 47 60 68 18 34 48 60 69 84 91 19 35 49 61 70 85 94 21 36 50 61 73 85 95 37 51 62 73 87 96 52 41 52 45 46 46 b 2 Q 54 60 Data are sorted and rounded to the nearest unit for simplicity From the data find a 1 Median c 2 Q

Show the work neatly clearly systematically and understandably USE PROPER NOTATION Do as shown in MY class 1 14 1 2 2 2 3 4 Consider the following frequency distribution of a population X 17 18 19 20 21 f 18 22 20 11 9 a Find the mode b Find the median c Find Q d Find Q3 e Find the mean by extending the table above and then show your computation below

Question 8 Y The median home value in Indiana and Nevada adjusted for inflation are shown below Year Indiana Nevada 1950 37700 53700 2000 94300 142000 If we assume that the house values are changing linearly a In which state have home values increased at a higher rate Select an answer 0 b If these trends were to continue what would be the median home value in Indiana in 2010 Submit Question c If we assume the linear trend existed before 1950 and continues after 2000 the two states median house values will be or were equal in what year The answer might be absurd The year Question Help Video Message instructor

Suppose a researcher collects data on the pollen allergen levels measured in grains per cubic meter in the morning and evening in 35 cities The data is plotted with morning pollen allergen levels on the horizontal axis and evening pollen allergen levels on the vertical axis Dayton Ohio is an outlier in the y direction What must be true about this city Select all true statements This city is an influential observation The evening pollen allergen level for this city is much higher or lower than other cities in the data set that have similar morning pollen allergen levels The morning pollen allergen level for this city is much higher or lower than the rest of the cities in the data set The evening pollen allergen level for this city is much higher or much lower than the rest of the cities in the data set The absolute value of the residual of this city is large

Two fair 14 sided dice are rolled What is the conditional probability that at least one lands on 8 given that the dice land on different numbers T The probability is Simplify your answer

A survey recently went out to 15 university presidents across a certain country The data represents the ages of the different presid Use a stem and leaf plot that has two rows for each stem to represent their ages 53 62 55 50 58 59 61 67 55 61 54 62 55 54 72

A professor wanted to find a linear model that relates the number of hours a student plays video games each week h to the cumulative grade point average G of the student He obtained a random sample of 10 full time students at his college and asked each student to disclose the number of hours spent playing video games and the student s cumulative grade point average Complete parts a through f below Hours of Video Games per Week h O A Cumulative grade point average is being used to predict the number of hours B The number of hours and the cumulative grade point average are unrelated OC The number of hours is being used to predict cumulative grade point average OD The number of hours is directly related to the cumulative grade point average 4 DO23358812 0 0 10 Grade point Average G 3 39 2 95 3 14 2 72 3 59 2 68 2 21 2 94 1 93 2 91 a Explain why the number of hours spent playing video games is the independent variable and cumulative grade point average is the dependent variable Chong p answer below

Temperature 57 61 53 60 65 71 66 77 74 64 72 Ice Cream Sales 216 325 185 335 406 525 412 614 544 421 445 Use your calculator to find the line of best fit Round to two decimal places as needed Be sure to type in the entire equation Example y 4x 5 Type in the y too Try again Y 27 25X 1337 25 Edit my response If the temperature outside is 75 degrees how much would we expect to sell Round to the nearest dollar Submit

The distribution of lifetimes for a nickel metal hydride battery often found in hybrid vehicles is normally distributed with a mean of 90 000 miles and a standard deviation of 5 000 miles What is the probability that a nickel metal hydride battery will last more than 100 000 miles Round your answer to 3 decimal places A If you had 2 000 of these batteries how many would you expect to last more than 100 000 miles

93 liters is the same as how many gallons Hint 1 L 0 26 gal Round your answer to the nearest tenth

Temperature 57 61 53 60 65 71 66 77 74 Ice Cream Sales 216 325 185 335 406 525 412 614 544 421 Use your calculator to find the line of best fit Rour to two decimal places as needed Be sure to type in the entire equation Example y 4x 5 Type in the y too Submit If the temperature outside is 75 degrees how much would we expect to sell Round to the nearest dollar

A survey among seniors at a large university revealed that the number of hours spent studying the week before final exams was normally distributed with a mean of 30 hours and a standard devation of 7 What percent of seniors spent less than 25 hours studying Round your to 1 decimal place

Simplify Rationalize the denominator 2 2 C

How many gallons are there in 44 liters Hint 1 L 0 26 gal Round your answer to the nearest tenth