Exam #2 (elaborations) MATH 146 (MATH 146) Elementary Statistics

Stats: Summer 2024 Name___________________________
At Home Test 2

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6 points
1. A bag of 120 tulip bulbs contains 63 red tulip bulbs, 50 yellow tulip bulbs, and 7 purple tulip bulbs.
a) What is the probability that a randomly selected tulip bulb is red?
b) What is the probability that a randomly selected tulip bulb is not purple?
c) Would it be considered unlikely to get a purple bulb?




5 points
2. Does the following represent a probability distribution? Circle one: YES NO
• If no, say why not.
• If yes, give the mean and standard deviation of the probability distribution.

x P(x)
2 .21
3 .43
4 .16
5 .03
6 .12
10 .05

, 16 points
3. Suppose you flip a fair coin 20 times. Would each of the following results be unusual, unlikely, both, or
neither? For each, explain why. Your explanations should give specific probabilities.
a) Getting 9 heads.
Probability:
Circle One: UNUSUAL UNLIKELY BOTH NEITHER
Explain why.




b) Getting 6 heads.
Probability:
Circle One: UNUSUAL UNLIKELY BOTH NEITHER
Explain why.




c) Getting 4 or less heads.
Probability:
Circle One: UNUSUAL UNLIKELY BOTH NEITHER
Explain why.




d) Getting 20 heads.
Probability:
Circle One: UNUSUAL UNLIKELY BOTH NEITHER
Explain why.




10 points
4. You are working with a binomial distribution. Calculate the following probabilities:
a) With 10 trials and a .41 chance of success, the probability of exactly seven successes.
b) With 50 trials and a .39 chance of success, the probability of at least twenty-two successes.