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.
