15 Questions
| Total Attempts: 55900

Questions and Answers

- 1.Let A be a random variable with E(A) = 13 and Var(A) = 6. Which among the following is FALSE?
- A.
E(3A + 10) = 49

- B.
E(A2) = 175

- C.
Var(10) = 10

- D.
Var(2A) = 24

- 2.Which of the following datasets is skewed to the left?
- A.
1, 2, 3, 4, 8

- B.
10, 12, 14, 18, 20

- C.
1, 4, 6, 8, 10

- D.
3, 9, 9, 9, 15

- 3.Sam determined how much students spend per week on reading materials. He constructed separate graphs for those who live on campus and those who live off campus. From the plots, he concluded that those who live on campus and those who live off campus have almost the same spending habits, noting the medians of the two groups. Is his conclusion true, or false?
- A.
True

- B.
False

- 4.If X follows a normal distribution with mean equal to 10 and variance equal to 5 then P(X < 10) is ______.
- 5.If A and B are mutually exclusive events with P(A)=0.3 and P(B)=0.5, then P(A ∩ B)=0.15.
- A.
True

- B.
False

- 6.Confidence interval estimation for the difference of the mean of paired data requires us to compute for the absolute value of the difference of each pair of observations.
- A.
True

- B.
False

- 7.A coefficient of correlation for two variables X and Y equal to zero implies that X and Y are not correlated.
- A.
True

- B.
False

- 8.If the p-value for your test statistic satisfies p-value > 0.25 then:
- A.
You would not reject Ho for 𝛼 = 0.05.

- B.
You would reject Ho for 𝛼 = 0.05.

- C.
You would reject Ho for 𝛼 = 0.10.

- D.
Your acceptance region has a lower limit of 0.25.

- 9.Suppose a 95% confidence interval for μ1 – μ2 is (3.54, 5.61). Then this evidence supports the claim that μ1 exceeds μ2.
- A.
True

- B.
False

- 10.The level of significance (α) is the maximum probability of __________ the null hypothesis when it is ______ that the researcher is willing to commit.
- A.
Not rejecting, true

- B.
Not rejecting, false

- C.
Rejecting, true

- D.
Rejecting, false

- 11.If our data set consisted of rhe ages of a sample of 300 people, which of the following is the correct interpretation of P
_{70}= 30?- A.
At least 30 of the 300 people are 70 or younger.

- B.
At least 210 of the 300 people are 30 or younger.

- C.
At least 30 of the 300 people are 30 or younger.

- D.
At least 70 of the 300 people are 30 or younger.

- 12.If the population of a certain country is comprised mostly of young people then the histogram of ages will appear to be
- A.
Positively skewed

- B.
Negatively skewed

- 13.We are given 𝑃(𝐴
^{𝑐}) = 0.6, 𝑃(𝐵^{𝑐}) = 0.3, and 𝑃(𝐴 ∩ 𝐵) = 0.2. Find 𝑃(𝐴 ∪ 𝐵).- A.
0.7

- B.
0.9

- C.
0.6

- D.
0.5

- 14.Of the 120 auto ignition circuits, 30 are defective. Let A = the number of nondefective ignition circuits in a random sample of 10 circuits. We can say that the distribution of A is binomial with n = ____ and p = _____.
- A.
10, 0.25

- B.
10, 0.33

- C.
10, 0.67

- D.
10, 0.75

- 15.The central limit theorem works only when the population comes from the normal distribution.
- A.
True

- B.
False