33 a 78 b 75 c 72 d 68 34 a 408 b 415 c 433 d 450 35

You see a TV commercial that states that “seven out of ten physicians surveyed prefer the
ingredients in pain reliever X to plain aspirin.” You write the company because you are
curious about the survey, and to your amazement, you find that the survey was of exactly
ten physicians. Suppose the population of physicians was indifferent as to the advertised
product and plain aspirin, that is, 50% preferred aspirin and 50% preferred the advertised
product. What is the probability that a survey of ten randomly selected physicians would
find seven or more who preferred the advertised product?
P(70 ≤ x ≤ 80) = ________
34
a
In the previous question, what is the standard deviation of the number of vehicles violating
the speed limit?
35
If the state police issued $180 speeding ticket to each speedster, what is the expected value
of the amount collected from speeding tickets?
a $13,500
b $12,750
c $12,250
d $11,200
33
In repeated experiment of clocking 100 vehicles what is the expected value of the number of
vehicles which violate the speed limit?
a 78
b 75
c 72
d 68

x*f(x) x2 x2*f(x) x*4 x*f(x) x2 x2*f(x)

1 2500 50 -400 -8 160000 3200
5 10000 500 -200 -10 40000 2000
15 22500 2250 0 0 0 0
87.5 122500 30625 800 200 640000 160000
200 160000 80000 1000 500 1000000 500000
27 202500 12150 1200 72 1440000 86400
11 302500 6050 1600 32 2560000 51200
346.5 822500 131625 786 802800