Prob Stat Normal Distribution

What is the rejection region of the given normal curve at the right?

• 𝑧≥1.28

• 𝑧≥1.645

• 𝑧≥1.96

• 𝑧≤2.33

Based on the graph, which of the following is TRUE?

• This is a two-tailed test.

• This is a right-tailed test.

• Level of significance is 0.025.

• The rejection region is 𝑡≤ -1.725.

In a left-tailed test with 𝛼=0.01, the critical value of z is:

• -2.576

• -2.330

• -1.960

• -1.645

What is the critical value if the population variance is known, 𝑎=0.025, and it is a two-tailed test?

• 𝑧=±1.28

• 𝑧=±1.645

• 𝑧=±1.96

• 𝑧=±2.33

This data is normally distributed.  What percent of the data is in the shaded region?

• 68%

• 95%

• 99.7%

• 50%

Which best describes the shaded part of this normal distribution graph?

• All data that is one or higher.

• All data that is one or more standard deviations above the mean.

• All data that is between 1 and 3.

• All data that is above the mean.

This data is normally distributed.  What percent of the data is in the shaded region?

• 68%

• 95%

• 99.7%

• 50%

This data is normally distributed.  What percent of the data is in the shaded region?

• 5%

• 95%

• 2.5%

• 50%

This data is normally distributed. What percent of the data is in the shaded region?

• 68%

• 95%

• 99.8%

• 50%

A grading scale is set up for 1000 students' test scores. It is assumed the scores are normally distributed with a mean score of 75 and a standard deviation of 15.

If a grade of a 60 is the lowest passing score, how many students are expected to pass the test? ​ (a)  

How many students are expected to fail the test? ​ (b)  

• 840 students

• 160 students

• 84 students

• 16 students

• 877 students

• 123 students