Question

USING Graphing Calculator: TI 84+ AND +4 METHOD, NOT WALDS (please:))

The test statistic of z=-2.50 is obtained when testing the claim that p<0.75

a. find the critical value(s)

b. Using sig. level alpha=0.05 should we reject null or fail to reject null?

Answer 1

Solution:

Given: The test statistic of z=-2.50 is obtained when testing the claim that p<0.75

Part a) find the critical value(s)

We have to use TI 84 plus calculator to find critical value.

Since this is left tailed test , we have one critical value which is in left tail.

Level of significance = 0.05

Use following steps in TI 84:

Press 2ND and VARS

Select invNorm(

Enter Numbers:

Area is level of significance

For z , Mean is 0 and standard deviation is 1.

Click on Paste and press Enter two times.

Thus

z critical value = -1.64485

z critical value = -1.645

( Round answer to specified number of decimal places)

Part b) Using sig. level alpha=0.05 should we reject null or fail to reject null?

Decision Rule:
Reject null hypothesis ,if z  test statistic value < z critical value = -1.645 , otherwise we fail to reject H0.

Since z test statistic = z = -2.50 < z critical value = -1.645 , we should reject null hypothesis H0.