Question

An earlier exercise posed the following research question: "Many cars have a recommended tire pressure of 32 psi (pounds per square inch). At a roadside vehicle safety checkpoint, officials plan to randomly select 60 cars for which this is the recommended tire pressure and measure the actual tire pressure in the front left tire. They want to know whether drivers on average have too little pressure in their tires." Suppose that the experiment is conducted, and the mean and standard deviation for the 60 cars tested are 29.8 psi and 3 psi, respectively. Carry out the five steps to test the appropriate hypotheses using α = 0.05. (Use a p-value, not a rejection region. Use α = 0.05.) Set up the null and alternative hypothesis. (Enter != for ≠ as needed.)

H0:

Ha:

Compute the test statistics for this situation. (Round your answer to two decimal places.) t =

Calculate the p-value for the test. (Use technology to calculate the p-value. Round your answer to four decimal places.) p-value =

Answer 1

using excel>addi>phstat>one sample test

we have

t Test for Hypothesis of the Mean
Data
Null Hypothesis                m=	32
Level of Significance	0.05
Sample Size	60
Sample Mean	29.8
Sample Standard Deviation	3
Intermediate Calculations
Standard Error of the Mean	0.387298335
Degrees of Freedom	59
t Test Statistic	-5.680375574
Lower-Tail Test
Lower Critical Value	-1.671093032
p-Value	2.17851E-07
Reject the null hypothesis

H0:u =32

Ha: u <32

Compute the test statistics for this situation. = -5.68

Calculate the p-value for the test. = 0.000