Question

Choose:

1. Compute a 99% confidence interval for mu if x-bar = 16.3, s = 1.5, and n = 25.

a. 16.3+/-0.8391          b. 16.3+/-0.774            c. 16.3+/-0.8361          d. 16.3+/-0.16782        e. not given

2. Assume Ho: mu </= 80 with s = 10, n = 50, and x-bar = 83. Find the p-value.

a. 1.414           b. 0.483           c. 0.017           d. 2.12             e. not given

3. A company claims a mean battery life of 42 months. A sample of 36 yields a mean of 39 months

with a standard deviation of 7 months. Test the null hypothesis, Ho: mu >/=42 with alpha 0.05.

a. Fail to reject Ho      b. Reject Ho    c. Fail to reject Ha      d. Reject Ha    e. not given

4. Match:

a. Probability Density Function

b.Cumulative Density Function

WITH

x. Rule giving a probability value

y. Rule giving a probability area

Answer 1

Q 1) 99% CI

Since population standard deviation is unknown, we use t distributio to find CI

Degrees of freedom = n-1= 24

The critical value of t for 24 df with 99% confidence is 2.797

Therefore the 99% CI is

Answer: Option a)

Q 2)

Since population standard deviation is unknown, we use t distribution

Under H0, the test statistic is

Degrees of freedom = n-1= 50-1= 49

The P-Value is 0.0195

Answer: Option e) not given

Q 3)  

Under H0, the test statistic is

Significance Level

Degrees of freedom = n-1= 36-1= 35

The P-Value is .007275

Since p value is less than significance level, Reject H0

Answer: b. Reject Ho  

Q 4) Answer: a. Probability Density Function - x. Rule giving a probability value

b.Cumulative Density Function - y. Rule giving a probability area