Question

A traffic study was conducted on a particularly busy section of street. The peak traffic flow was averaged over a 5 day period and the following results were determined: peak flow mean = 160.4 cars; peak flow variance = 30.5 cars²

The traffic study was done to determine if more than 150 cars were passing through the section during peak periods on average. Hypothesis testing was performed, with the alternative hypothesis being that more than 150 cars are passing through the intersection. Taking into account the limited number of measurements, what are the results of the test?

a. Fail to reject the null; p = 0.99

b. Reject the null in favor of the alternative; p = 1.3E-5

c. Reject the null in favor of the alternative; p = 0.007

d. Fail to reject the null; p = 0.007

e. none of these

Which of the following can we say for certain about the data? (select all that apply)

Which of the following can we say for certain about the data? (select all that apply)

(a)μ = 160.4

(b) df or ν = 4

(c) sigma =5.5

(d) standard error =2.5

(e) none of these

Answer 1

Ho: = 150

Ha: > 150

Null hypothesis states that on an average 150 cars are passing through the intersection.

Alternative hypothesis states that on an average more thatn 150 cars are passing through the intersection.

Step 2:

n = 5

sample mean = 160.4

sample sd = sqrt(30.5) = 5.523

p value = TDIST ( 4.211, 4, 1) =  0.0068

Step 3:

is not given, we assume = 0.05

As p value (0.007) is less than , we reject the Null hypothesis.  

Reject the null in favor of the alternative; p = 0.007

Which of the following can we say for certain about the data? (select all that apply)

(b) df or ν = 4

(c) sigma =5.5

(d) standard error =2.5