Q4 Review in Statistics

Which of the following defines the area encompassed by the values not included in the non-rejection or acceptance region or also the area of the tails of the distribution?

• critical value  

• rejection region  

• level of significance

• population variance

For a two-tailed test with variance unknown, n= 16, and 𝛼 = 0.05, what is the critical value?

• ±2.092

• ±2.134 

• ±2.145 

• ±2.145

If the level of significance decreased from 0.1 to 0.05, then the boundaries for the critical region move farther away from the center of the distribution.

• True

• False

• Neither A and B

• Either A and B

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.

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  

On the given figure below, the t-computed value is 1.217. What conclusion can be drawn?

• Reject the null hypothesis.

• Fail to reject the null hypothesis.

• Reject both the null and alternative hypotheses.

• Support both the null and alternative hypotheses.

A researcher thinks that if expectant mothers use vitamins, the birth weight of the babies will increase. The average birth weight of the population is 3.9 kgs. What is the alternative hypothesis?

• 𝐻𝑎: 𝜇 < 3.9       

• 𝐻𝑎: 𝜇 > 3.9  

• 𝐻𝑎: 𝜇 = 3.9     

• 𝐻 𝑎: 𝜇 ≠ 3.9  

Which of the following is NOT a consideration in using z-test/statistic?

• Variance is known.

• Sample standard deviation is known.

• The population mean is less than 30.

• Population standard deviation is known.

If in a sample n=16 selected from a normal population, 𝑥¯ = 56 and 𝑠 = 12, what statistical test is applicable to be used?

• f-test    

• t-test    

• z-test    

• Central Limit Theorem

A positive association on a scatter plot implies that ___________.

• Y remains unchanged as X increases

• Y changes randomly as X increases       

• Y decreases as X increases

• Y increases as X increases