15 Questions

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.
- 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