Question

2.

a.

A meteorologist claims that the average high temperature for the month of August in Philadelphia, PA. is 83 degrees Fahrenheit. If the residents of Philadelphia do not believe this to be true, what hypotheses should they test?

Ho: u > 83 degrees Fahrenheit vs. Ha: u < 83 degrees Fahrenheit

Ho: u = 83 degrees Fahrenheit vs. Ha: u < 83 degrees Fahrenheit

Ho: u < 83 degrees Fahrenheit vs. Ha: u > 83 degrees Fahrenheit

Ho: u = 83 degrees Fahrenheit vs. Ha: u does not = 83 degrees Fahrenheit

Ho: u = 83 degrees Fahrenheit vs. Ha: u > 83 degrees Fahrenheit

b.

The manufacturer of a particular battery pack for laptop computers claims its battery packs can function for 9 hours, on the average, before having to be recharged. A competitor claims that the manufacturer's claim is too high. A random sample of 38 battery packs was selected and placed on test. The mean functioning time before having to be recharged was 7.6 hours with a standard deviation of 1.7 hours. Perform the appropriate test of hypothesis to determine whether the competitor is correct. Test using alpha = 0.05. Calculate the test statistic and round your answer to the hundredths place.

		Test statistic = -31.29
		Test statistic = -1.42
		Test statistic = -6.62
		Test statistic = -6.62
		Test statistic = -5.08

Answer 1

Solution:

Given that,

= 9

= 7.6

s = 1.7

n = 38

The test statisc t is,

t = ( -  ) /  (s /n)

t =( 7.6 - 9) / (1.7 / 38)

t = ( - 1.4*  38 ) / 1.7

t = -5.08

Test staistic = -5.08

Using t distribution table

P value = 0.9977

P value >  

1 > 0.05

Do not reject  the null hypothesis .