/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Q. 52. Ice cream For a statistics class... [FREE SOLUTION] | 91影视

91影视

Ice cream For a statistics class project, Jonathan and Crystal held an ice-cream-eating contest. They randomly selected 29 males and 35 females from their large high school to participate. Each student was given a small cup of ice cream and instructed to eat it as fast as possible. Jonathan and Crystal then recorded each contestant鈥檚 gender and time (in seconds), as shown in the dot plots.

Do these data give convincing evidence of a difference in the population means at the 伪=0.103051526=0.200=20.0%=0.10 significance level?

a. State appropriate hypotheses for performing a significance test. Be sure to define the parameters of interest.

b. Check if the conditions for performing the test are met.

Short Answer

Expert verified

Part a) The hypothesis is:

H0:1=2H0:1notequalto2

Part b) All conditions are not met.

Step by step solution

01

Part a) Step 1: Given information

The given claim is that a difference in the means.

02

Part b) Step 2: Explanation

We must now determine the appropriate hypotheses for performing a significance test.

As a result, the claim represents either the null hypothesis or the alternative hypothesis. According to the null hypothesis, the population proportions are equal. If the claim is the null hypothesis, then the alternative hypothesis states the inverse of the null hypothesis.

Therefore, the following are the appropriate hypotheses:

H0:1=2Ha:1notequalto2

1=the true mean time for males to eat ice cream.

2= the true mean time for females to eat ice cream.

03

Part b) Step 1: Explanation

There are three requirements that must be met:

It is satisfying because the samples are drawn at random from different populations.

Independent: It is satisfying because the sample of 29male students represents less than 10%of the total population of male students, and the sample of 35female students represents less than 10%of the total population of female students.

Normal: It is not satisfactory because the sample size for male students is small and the male distribution is not approximately Normal, as shown by the skewed pattern in the dot plot.

Therefore, all the conditions are not satisfied since the large sample condition is not satisfied and it is then not appropriate to perform a hypothesis test for the mean difference.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91影视!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

At a baseball game, 42of 65randomly selected people own an iPod. At a rock concert occurring at the same time across town, 34of 52randomly selected people own an iPod. A researcher wants to test the claim that the proportion of iPod owners at the two venues is different. A 90%confidence interval for the difference (Game 鈭 Concert) in population proportions is (0.154,0.138). Which of the following gives the correct outcome of the researcher鈥檚 test of the claim?

a. Because the confidence interval includes 0, the researcher can conclude that the proportion of iPod owners at the two venues is the same.

b. Because the center of the interval is -0.008, the researcher can conclude that a higher proportion of people at the rock concert own iPods than at the baseball game.

c. Because the confidence interval includes 0, the researcher cannot conclude that the proportion of iPod owners at the two venues is different.

d. Because the confidence interval includes more negative than positive values, the researcher can conclude that a higher proportion of people at the rock concert own iPods than at the baseball game.

e. The researcher cannot draw a conclusion about a claim without performing a significance test.

Children make choices Many new products introduced into the market are

targeted toward children. The choice behavior of children with regard to new products is of particular interest to companies that design marketing strategies for these products. As part of one study, randomly selected children in different age groups were compared on their ability to sort new products into the correct product category (milk or juice). Here are some of the data:

Researchers want to know if a greater proportion of 6- to 7-year-olds can sort correctly than 4- to5-year-olds.

a. State appropriate hypotheses for performing a significance test. Be sure to define the parameters of interest.

b. Check if the conditions for performing the test are met.

The power takeoff driveline on tractors used in agriculture is a potentially serious hazard to operators of farm equipment. The driveline is covered by a shield in new tractors, but for a variety of reasons, the shield is often missing on older tractors. Two types of shields are the bolt-on and the flip-up. It was believed that the boll-on shield was perceived as a nuisance by the operators and deliberately removed, but the flip-up shield is easily lifted for inspection and maintenance and may be left in place. In a study initiated by the US National Safety Council, random samples of older tractors with both types of shields were taken to see what proportion of shields were removed. Of 183tractors designed to have bolt-on shields, 35had been removed. Of the 156tractors with flip-up shields, 15were removed. We wish to perform a test of H0:pb=pfversus Ha:pb>pf, where pband pfare the proportions of all the tractors with bolt-on and flip-up shields removed, respectively. Which of the following is not a condition for performing the significance test ?

(a) Both populations are Normally distributed.

(b) The data come from two independent samples.

(c) Both samples were chosen at random.

(d) The counts of successes and failures are large enough to use Normal calculations.

(e) Both populations are at least 10times the corresponding sample sizes.

Which inference method?

a. A city planner wants to determine if there is convincing evidence of a difference in the average number of cars passing through two different intersections. He randomly selects 12times between 6:00a.m. and 10:00p.m., and he and his assistant count the number of cars passing through each intersection during the 10-minute interval that begins at that time.

b. Are more than 75%of Toyota owners generally satisfied with their vehicles? Let鈥檚 design a study to find out. We鈥檒l select a random sample of 400 Toyota owners. Then we鈥檒l ask each individual in the sample, 鈥淲ould you say that you are generally satisfied with your Toyota vehicle?鈥

c. Are male college students more likely to binge drink than female college students? The Harvard School of Public Health surveys random samples of male and female undergraduates at four-year colleges and universities about whether they have engaged in binge drinking.

d. A bank wants to know which of two incentive plans will most increase the use of its credit cards and by how much. It offers each incentive to a group of current credit card customers, determined at random, and compares the amount charged during the following 6 months.

Men versus women The National Assessment of Educational Progress (NAEP)

Young Adult Literacy Assessment Survey interviewed separate random samples of840

men and 1077women aged 21to 25years.

The mean and standard deviation of scores on the NAEP鈥檚 test of quantitative skills were x1=272.40and s1=59.2for the men in the sample. For the women, the results were x 虅2=274.73and s2=57.5.

a. Construct and interpret a 90% confidence interval for the difference in mean score for

male and female young adults.

b. Based only on the interval from part (a), is there convincing evidence of a difference

in mean score for male and female young adults?

See all solutions

Recommended explanations on Math Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.