Statistics: CAIS 101-What would be a natural null hypothesis for

Statistics: CAIS 101-What would be a natural null hypothesis for

Subject: Mathematics    / Statistics
Question
7.1 What would be a natural null hypothesis for the research question of whether or

not the average US passenger car gets more than 30 miles per gallon? What alternative

hypothesis would you use?

7.3 Researchers used a random sample to test the null hypothesis that the average

age of people visiting an Internet site is 25. Which of the following results has

the higher t value for a test of this null hypothesis? Do not do any calculations;

just explain your reasoning.

a. x ¼ 26:43; s ¼ 7:17; n ¼ 50

b. x ¼ 32:14; s ¼ 7:17; n ¼ 50

7.4 Which of the following results has the higher t value for a test of the null hypothesis

that the average speed on a 40 miles-per-hour street is 40 miles per hour?

Do not do any calculations; just explain your reasoning.

a. x ¼ 43:71; s ¼ 14:88; n ¼ 60

b. x ¼ 43:71; s ¼ 8:06; n ¼ 60

7.7 Which of the following assumptions were used in calculating the P value in the

preceding exercise?

a. Temperatures for healthy adults are normally distributed.

b. These 50 observations are a random sample.

c. The mean temperature for unhealthy adults is higher than the mean temperature

for healthy adults.

d. On average, healthy adults have a temperature of 98.6 Fahrenheit.