Fewer than 90% of adults have a cell phone. This is a claim about a population proportion so a normal distribution is assumed. The claim undergoes a hypothesis test using a significance level of α =...

Fewer than 90% of adults have a cell phone. This is a claim about a population proportion so a normal distribution is assumed. The claim undergoes a hypothesis test using a significance level of α = 0.05. The P-value based on sample data is calculated to be 0.0003.

1.  Find the z-score for a significance level of a = 0.05.  This is the critical value. What is it?

2. Sketch a normal distrbution curve, plot the critical value, and highlight the critical or rejection region .

3.  The z test stastic based on sample data is -3.4. Find -3.4 on the z-score table. What is the cumulative area from the LEFT?

4. State a conclusion about the null hypothesis (reject H0 or fail to reject H0).