We want to test whether the data taken from 20 test experiments is less than or 0 (µ < 0).

a. What is the null hypothesis Ho for our test (remember Ho always has an equals sign in it by convention) ?

b. What is the alternative hypothesis Ha?

c. What type of tail test will we use? (left tail, right tail, or two tails)?

d. What is the mean of the sample xbar?

e. What is the standard deviation of the sample s?

f. What is the size of the sample n?

g. We going to use a t-statistic. Explain why we are not going to use a z-statistic.

h. Calculate the t-statistic using xbar, µ, n, and s.

i. How many degrees of freedom does this data set have?

j. Use the t-distribution calculator to compute a p-value. Include a screen shot of your answer.

k. Typically, we want a 90% confidence level. Based on your value of p, should we accept or reject the null hypothesis?

l. What if we want a 95% confidence level? Based on your value of p, should we accept or reject the null hypothesis?

Data

-1

2

-3

1

-1

0

-4

5

-2

1

-3

2

-1

2

-4

3

0

1

-2

2

**Subject Mathematics General Statistics**