NPTEL Data Analytics with Python Week4 : Assignment 4 Answers 2022

If we have a sample size of 20 and population standard deviation is known, we will use:

t- test for hypothesis testing

z-test for hypothesis testing

both t and z test

F-test

1 point

Null hypothesis, Ho: mu1- mu2 = 0 is a:

Upper tail test

Lower tail test

Two tail test

F-test

1 point

The quality-control manager at a Li-BATTERY factory needs to determine whether the mean life of a large shipment of Li-Battery is equal to the specified value of 375 hours. The process standard deviation is known to be 100 hours. A random sample of 64 batteries indicates a sample mean life of 350 hours.

State the null and alternative hypotheses

Mu = 375

Mu ≤ 375

Mu = 350

Mu ≥ 350

1 point

At the alpha = 0.05 level of significance is there any evidence that the mean life is different from 375 hours?

Yes, there is

No, there is not

None of these

1 point

For one-tailed test, the test statistic z is determined to be zero. The p-value for this test is:

Zero

-0.5

+0.5

1.0

1 point

The error of rejecting a true null hypothesis is:

a Type I error

a Type II error

is the same as Beta

committed when not enough information is available

1 point

The mean cost of a hotel room in a city is said to be $168 per night. A random sample of 25 hotels resulted in X-bar = $172.50 and sample standard deviation s = 15.40. Calculate the t statistic.

-2

1.46

-1.46

1 point

In hypothesis testing if the null hypothesis is rejected,

no conclusions can be drawn from the test

the alternative hypothesis is true

the data must have been accumulated incorrectly

the sample size has been too small

1 point

In the hypothesis testing procedure, alpha is

1 - the level of significance