questions 201-230 Flashcards
1
Q
- which of these statements is true about contiuous random variables and their probability distributions? I. The distribution is modeled by a probability distribution function that is non-negative. II. The probability of an individual event E is calculated by P(X=E). III. the total area of the curve is 1. a. I only b. I and II only c.I and III only d. II only e. III only
A
c
2
Q
- which of these statements is true about normal probability distribution? I. U = O and mean = 1 only II. It is symmetric about U with tails extending to positive and negative infinity. III. The total area under the curve cannot be determined because the tails are asymptotic to the horizontal axis. a. I only b. I and II only c.I and III only d. II only e. III only
A
D
3
Q
- Which of the following is true about the necessary conditions for using the normal probability distribution? I. is U=O and mean = 1, you know that the distribution is normal. II. the normal distribution can be used at any time regardless of a populations distribution. III. when is it known that a distribution is approximately normal, the normal distribution may be used. a. I only b. I and II only c.I and III only d. II only e. III only
A
E
4
Q
- in the standard normal distribution, what is the probability that z >(or = to) 1.25? a. 0.8925 b. 0.8962 c. 0.8944 d. 0.1056 e. 0.1038
A
d
5
Q
- in the standard normal distribution what is the probability that -2.95
A
d
6
Q
- the average height of women between the ages to 30-39 is 163,2 centimeters with a SD of 9.3 centimeters. Find the probability that a woman in this age group is over 160 cm if it is known that the distribution is approx normal. a.0.3669 b. 0.3655 c. 0.6331 d. 0.6360 e. 0.3660
A
c
7
Q
- the average weight of men between the ages of 40-49 is 202,3 lbs with a SD of 50.7 lbs. find the probability that a man in this age group is under 180 lbs if it is known that the distribution is approx normal. a.0.6700 b.0.6331 c.0.3301 d.0.3300 e.0.3669
A
d
8
Q
- the average weight of men between the ages of 20-29 is 188.3 lbs with a SD of 66.4 lbs. the average weight of women between the ages 20-29 is 155.9 lbs with a SD of 60.3 lbs. if it is known that the distributions are approx normal. which of the following statements is true? I. A woman weighing 215 lbs is more likely than a man weighing 255 lbs. II. A man weighing 255 lbs is more likely than a woman weighing 215lbs. III. they are equally likely. a. I only b. I and II only c.I and III only d. II only e. III only
A
a
9
Q
- If SAT scores are normally distributed with a mean of 500 and an SD of 100, what minimum score is needed to ensure that you are in the top 7%? a. 640 b.500 c.645 d.650 e.648
A
e
10
Q
- the average body mass index value of children 9 years old is 18.4 with a SD of 4.5. if it is known that the distributions are approx normal, whats the index for children at the 82nd percentile. a. 22.6 b.22.0 c.23.0 d.0.92 e.0.82
A
a
11
Q
- which of these statements is true about the law of large numbers? I. 100 trials will be enough to determine the true proportion in the population. II. over time the proportion of success in a stimulation approaches the true proportion in the population. III. the relative frequency of success from just a few trials accurately approximates the true probability of success. a. I only b. I and II only c.II only d. I and III only e. III only
A
c
12
Q
- what would be an appropriate way to assign digits in order to stimulate flipping an unfair coin with P(H)=0.3? a.assign digits 1,2,3 to be a head. assign digits 4-9 to be a tail b.assign digits 0,1,2,3 to be a head and assign digits 4-9 to be a tail c. assign digits 0,1,2,3 to be a tail, assign digits 4-9 to be a head. d.assign digits 0,1,2 to be a tail, assign digits 3-9 to be a head e. assign 0,1,2 to be a head and assign digits 3-9 to be a tail.
A
e
13
Q
213
A
C
14
Q
214.
A
e
15
Q
215
A
d
16
Q
216
A
d
17
Q
217
A
c
18
Q
218
A
a
19
Q
219
A
d
20
Q
220
A
21
Q
221
A
a
22
Q
222
A
a
23
Q
223
A
24
Q
224
A
25
Q
225
A
26
Q
226
A
b
27
Q
227
A
b
28
Q
228
A
a
29
Q
229
A
c
30
Q
230
A
a
