A maintenance supervisor is comparing the standard version of an instructional booklet with one that has been claimed to be superior. An experiment is conducted in which 26 technicians are divided into two groups, provided with one of the booklets, then given a test a week later. For the 13 using the standard version, the average exam score was 72.0, with a standard deviation of 9.3. For the other 13 using the new version, the average score was 80.2, with the standard deviation of 10.1. Assume normal populations with equal standard deviations, and using the 5% level of significance, does the standard version booklet appear to be better than the new version?

A study compared the cost of restaurant meals when people pay individually versus splitting the bill as a group. In the experiment half of the people were told they would each be responsible for individual meals costs and the other half were told the cost would be split equally among the six people at the table. The 24 people paying individually had a mean cost of 37.29 Israeli shekels with a standard deviation of 12.54, while the 24 people splitting the bill had a higher mean cost of 50.92 Israeli shekels with a standard deviation of 14.33. The raw data can be found in SplitBill and both distributions are reasonably bell-shaped. Use this information to find a 95 % confidence interval for the difference in mean meal cost between these two situations. Click here for the dataset associated with this question. Round your answers to two decimal places. The 95 % confidence interval is ! to i

According to the U.S. Census, the average adult woman is the United States is 65 inches tall and the standard deviation is 3 inches.  If Zsike is 67 inches tall, what is her z-score?

In the United States, egg sizes are set by the Department of Agriculture. A "large" egg, for example, weighs between 57 and 64grams. Suppose the weights of eggs produced by hens owned by a particular farmer are approximately normally distributed with a mean of 55.8 grams and a standard deviation of 7.5 grams. What proportion of these eggs weigh less than 50grams? What percent of these eggs would be classified as large?

Five students took a self-confidence test. Their deviation scores were –4, +3, +1, –2, and +2. Assuming that these scores com form a normaldistribution, which deviation represents the highest raw score?

One year Terry had the lowest ERA (earned-run average, mean number of runs yielded per nine innings pitched) of any male pitcher at his school, with an ERA of 3.02. Also, Karen had the lowest ERA of any female pitcher at the school with an ERA of 3.24. For the males, the mean ERA was 4.364 and the standard deviation was 0.639. For the females, the mean ERA was 3.801 and the standard deviation was 0.959 Find their respective z-scores. Which player had the better year relative to their peers, Terry or Karen? (Note: In general, the lower the ERA, the better the pitcher.) Terry had an ERA with a z-score of Karen had an ERA with a z-score of (Round to two decimal places as needed) Which player had a better year in comparison with their peers? OA. Terry had a better year because of a higher z-score. OB. Karen had a better year because of a lower z-score. OC. Terry had a better year because of a lower z-score. O D. Karen had a better year because of a higher z-score. GIL

The mean Math ACT score was 20.5, with a standard deviation of 5.5. Sarah scored a 26 on the Math ACT. According to the empirical rule, what percent of students taking the Math ACT scored higher than Sarah? O 5.5% O 16% O 84% O 2.5%

A survey found that the mean commute time is 25.4 minutes for the fifteen largest U.S. cities.The Austin, TX, chamber of commerce feels that Austin's commute time is less. A survey of 25 randomly selected commuters had a mean of 22.1 minutes with a standard deviation of 5.3 minutes. At the 10% level, does the survey data suggest that Austin commute time is significantly less than the national average? Your answer should have the following: 1). Null hypothesis:2). Alternative hypothesis: 3). Test Type: P-test

Reports on a student's ACT, SAT, or MCAT usually give the percentile as well as the actual score. The percentile is the cumulative proportion stated as a percentage: the percentage of all scores that were lower than this one. In 2019, the scores on the Mathematics portion of the SAT were close to Normal, with mean 528528 and standard deviation 117. Joseph scored 411.411. What was his percentile?

A report about how American college students manage their finances includes data from a survey of college students. Each person in a representative sample of 793 college students was asked if they had one or more credit cards and if so, whether they paid their balance in full each month. There were 500 who paid in full each month. For this sample of 500 students, the sample mean credit card balance was reported to be $825. The sample standard deviation of the credit card balances for these 500 students was not reported, but for purposes of this exercise, suppose that it was $205. Is there convincing evidence that college students who pay their credit card balance in full each month have a mean balance that is lower than $907, the value reported for all college students with credit cards? Carry out a hypothesis test using a significance level of 0.01.   State the appropriate null and alternative hypotheses. H0: ? = 907 Ha: ? < 907 H0: ? = 907 Ha: ? > 907      H0: ? < 907…