Question

Question 10

"D" size batteries produced by MNM Corporation have had a life expectancy of 87 hours. Because of an improved production process, the company believes that there has been an increase in the life expectancy of its "D" size batteries. A sample of 36 batteries showed an average life of 88.5 hours. Assume from past information that it is known that the standard deviation of the population is 9 hours.

Using a 0.01 level of significance, the observed value of the test statistic is

Group of answer choices

1

1.5

-1.5

none of the above

Question 11

"D" size batteries produced by MNM Corporation have had a life expectancy of 87 hours. Because of an improved production process, the company believes that there has been an increase in the life expectancy of its "D" size batteries. A sample of 36 batteries showed an average life of 88.5 hours. Assume from past information that it is known that the standard deviation of the population is 9 hours.

Using a 0.01 level of significance, the p-value is

Group of answer choices

0.2644

0.8413

0.1587

0.7356

Answer 1

Solution :

Given that ,

Q - 10

= 87  

= 88.5

= 9

n = 36

This is the right tailed test .

The null and alternative hypothesis is ,

H0 :   = 87

Ha : > 87

Test statistic = z

= ( - ) / / n

= ( 88.5 - 87 ) / 9 / 36

= 1

The test statistic = 1

Correct option ; - 1

Q - 11

Given that ,

= 87  

= 88.5

= 9

n = 36

This is the right tailed test .

The null and alternative hypothesis is ,

H0 :   = 87

Ha : > 87

Test statistic = z

= ( - ) / / n

= ( 88.5 - 87 ) / 9 / 36

= 1

The test statistic = 1

P - value = P ( Z > 1 )

= 1 - P ( Z < 1 )

= 1 - 0.8413

= 0.1587

P-value = 0.1587

Correct ; - 0.1587