What statement below is true about the ages of these students when considering standard deviations?

It seems these days that college graduates who are employed full time work more than 40 hour weeks. Data are available that can help us decide if this is true. A survey was recently sent to a group of adults selected at random. There were 22 respondents who were college graduates employed full time. The mean number of hours worked per week by these 22 respondents was 43 hours, with a standard deviation of 8 hours.  Assume that the population of hours worked per week by college graduates employed full time is normally distributed with mean. Can we conclude that mean is greater than 40 hours? Use the 0.1 level of significance. Perform a one tailed test, and complete the parts below.

In Professor Krugman’s economics course, the correlation between the students’ total scores prior to the final examination and their final‑examination scores is ?=0.5.r=0.5. The pre‑exam totals for all students in the course have mean 280280 and standard deviation 40.40. The final‑exam scores have mean 7575 and standard deviation 8.8. Professor Krugman has lost Julie’s final exam but knows that her total before the exam was 300.300. He decides to predict her final‑exam score from her pre‑exam total. (a) Which of the choices is the least‑squares regression line of final‑exam scores on pre‑exam total scores in this course?

The mean score for first exam in your first organic chemistry class (section A) was 60, with a standard deviation of 5. Your score on the exam was 70. A. How many standard deviations above the mean is your score?

The distribution of sample means for bi-monthly employee income at a particular company for samples of 70 employees is normal with a mean of $5921 and a standard deviation of $219. You take a random sample of 70 employees from the company and find that their mean bi-monthly income is $5668. How many standard deviations is the sample mean from the mean of the distribution of sample means?

A psychologist is studying the self image of smokers, as measured by the self-image (SI) score from a personality inventory. She would like to examine the mean SI score, µ, for the population of all smokers. Previously published studies have indicated that the mean SI score for the population of all smokers is 80 and that the standard deviation is 15, but the psychologist has good reason to believe that the value for the mean has changed. She plans to perform a statistical test. She takes a random sample of SI scores for smokers and computes the sample mean to be 88. Based on this information, complete the parts below. (a) What are the null hypothesis H. and the alternative hypothesis H₁ that should be used for the test? Ho : H₁ :0 (b) Suppose that the psychologist decides not to reject the null hypothesis. What sort of error might she be making? Type I Suppose the true mean SI score for all smokers is 80. Fill in the blanks to describe a Type I error. the hypothesis that u is (Choose…

Forty refrigerators from two different models of a refrigerator manufacturer are compared to see if the smaller model uses less energy than the larger model. The energy was measured in kilowatt hours per month (kwh/mo). From years of testing these models, it is known that the standard deviation of kwh/mo is 34 kwh/mo for the smaller model and 40 kwh/mo for the larger one. From this survey, the sample means and standard deviations are 125 and 34, and 90 and 40, respectively. If we conduct a hypothesis test, the decision and conclusion are   Group of answer choices   Do not reject the null hypothesis and conclude that the average kwh/mo are the same.   Reject the null hypothesis and conclude that the average kwh/mo are different.   Reject the null hypothesis and conclude that the average kwh/mo for the smaller refrigerator is higher than for the larger model.   Do not reject the null hypothesis and conclude that the average kwh/mo for the smaller refrigerator is higher than for…

In class A, Jamir got 85 for his first test. Jamir's class mean was 75 and the standard deviation was 5.In class B, Laurabelle got 80 in her first test. Laurabelle's class mean was 50 and the standard deviation was 10.In a fair comparison of the two students in two different classes, who did better in his or her test.  (Compare Jamir and Laurabelle's standing in their classes.Note Z-score gives that information.) Jamir Laurabelle Both did the same none of the above

According to the US Census Bureau. the number of people in a household has amean of 2.6 and a standard deviation of 1.5. Suppose the census bureauinstead had estimated this mean using a random sample of 225 homes and that sample had a mean of 2.4 and standar deviation of 1.4. Describe the center and spreadof the sample mean for 225 homes. What does the distribution describe?