Unit Test — Unit test Answers

In a large high school, 37% of the teachers believe that five minutes is not enough time for students to change classes. However, 89% of the students believe that five minutes is not enough time for students to change classes. Let and be the sample proportions of teachers and students, respectively, who believe that five minutes is not enough time for students to change classes. Suppose 28 teachers and 100 students are selected at random and asked their opinion on the amount of time students have to change class.Which of the following is the correct calculation and interpretation of the standard deviation of the sampling distribution of ?

The daily temperatures for the winter months in Virginia are Normally distributed with a mean of 59°F and a standard deviation of 10°F. A random sample of 10 temperatures is taken from the winter months and the mean temperature is recorded. What is the standard deviation of the sampling distribution of the sample mean for all possible random samples of size 10 from this population?

At a local veterinary office, 48% of dogs get their teeth cleaned, while 35% of cats get their teeth cleaned. Let and be the sample proportions of dogs and cats at this veterinary office, respectively, who get their teeth cleaned. Suppose 25 dogs and 32 cats from this veterinary office are selected at random to collect data on their teeth-cleaning history.Which of the following is the correct calculation and interpretation of the standard deviation of the sampling distribution of ?

Alex’s times for running a mile are Normally distributed with a mean time of 5.28 minutes and a standard deviation of 0.38 seconds. Chris’s times for running a mile are Normally distributed with a mean time of 5.45 seconds and a standard deviation of 0.2 seconds. Ten of Alex’s times and 15 of Chris’s times are randomly selected. Let represent the difference in the mean times for Alex and Chris. Which of the following represents the standard deviation of the sampling distribution for ?

The volume of liquid soap in containers labeled as 7 oz is approximately Normally distributed and has a mean of 7.15 oz and a standard deviation of 0.11 oz. If 8 bottles of the soap are randomly selected, what is the probability that the mean is less than 7.11 oz?