Question 650701: 5. max went to the mcg to practice his cricket max has determined that his prob of hitting a 4 of any ball when playing cricket is 0.07 wat is the lowest number of balls he must face to ensure that the prob of hitting more than 4 4’s is more than 0.8.
A 4
B 15
C 45
d 65
e 95
B) explain why A could not correct
7.Continous random variable X has a pdf given by f(x)= -3x/4 (x-2) |0
The mode of X:
A 0
B 0.75
C 1
D 1.5
E 2
B) explain why A is not correct
C) If the mean was found instead of the mode, which answer would be correct.
8. Pr(X<.5|X<1), correct to 4 dp
A 0.0781
B 0.1563
C 0.1582
D 0.3125
E 0.3164
B) using a sketch graph, explain why A is not correct
C) Keeping the question conditional, vary the it so that A is the solution
9. after the formal, tiff was evaluating fashion sense, she gave them ratings out of 50, rating were normally distributed with a mean of 30 and a variance of 49, if tiff awarded the best 8% a A+, then her cut off score to the nearest interger, for an A+ would have been.
A 10
B 20
C 35
D 40
E 50
B) Using a sketch graph, explain why A is not correct
C) change the wording of the questionn so B is correct
10.The random variable X has a normal distribution with mean 10 and Standard dev. 2, the prob that X is less than 5 given that it is less than 10 is closest to.
A 0.0062
B 0.0124
C 0.4969
D 0.5000
E 0.9938
B) Using a sketch graph explain why D is not correct
C) What is error if A was selected.
11.Past months indicate that if it rains on a particular day there is an 80% chance that it will rain the next day. If it does not rain on a particular day, the probability that it will rain the next day is p%. It rained on Monday and the probability that it rained on the following Wednesday was 65%. The value of p is:
A 5
B 10
C 15
D 20
E 35
B) Alter the question by changing either the 80% or the 65% or both so that D is correct.
12.The prob mr.bettiol wins any game is 0.4, no game can be a draw, if the prob that mr.purcell wins no game is less than 0.01, then minimum number games they play is equal to.
A 5
B 6
C 7
D 9
E 10
B) Only change the prob of mr.bettiol winning a game from 0.4, so that answer E is correct.
13.if X is normally distributed random variable with mean, µ, and variance (9 µ^2)/4, then
Pr(X>2 µ) is closest to.
A 0.023
B 0.252
C 0.504
D 0.672
E 0.748
B) explain why E is not correct.
14.Normally distrubted with a mean of 45 minutes and a Standard dev. of 8 minutes, if Z is the random variable of the standard normal distribution, the prob that Kate travel is more than 55 minutes is equal to.
A Pr(Z<1.25)
B 1-Pr(Z<1.25)
C Pr(Z>-1.25)
D Pr(Z<2)
E 1-Pr(Z<2)
B) What is the error if A was selected
C) Change the question so that D is correct.
15.She only runs north or east. If she run north for 1 block, the prob she will turn east at the nearest intersection is 0.6. if she runs east for 1 block, the prob that she will turn north at the nearest intersection is 0.75. Anja begins running north for the first block, what is the prob she will turn north at the 5th intersection that she encounters.
A 0.44
B 0.45
C 0.55
D 0.56
E 0.66
B) if the question was long term rather 5th intersection, which solution is correct.
Answer by Aaniya(63)   (Show Source):
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