Ap stat chap 6
A random variable Y has the following distribution: {table} the value of constant C is:
A. .10
Let the random variable x represent the weight of male black Bears before they begin hibernation. Research has shown that the x is approximately normal distributed with a mean of 250 pounds and a standard deviation of 50 pounds.
A. 0.0668
In order for the random variable x to have a geometric distribution, which of the following conditions must x satisfy? (1,2,3,4,5 choices)
A. 3&4
A set of two cards consist of five red cards and five black cards. The cards are shuffled thoroughly and you turn cards over, one at a time, beginning with the top card. Let Y be the number of cards you turn over until you observe the first red card. The random variable Y has which of the following probability distributions?
E. None of the above
A rock concert producer has scheduled an outdoor concert. If it is warm that day she expects to make a $20,000 profit. If it is cool that day, she expects to make a $5000 profit if it is very cold that day she expects to suffer a $12,000 loss. Based upon historical records, the weather office has estimated the chance of a warm day to be 0.60; the chances of a cool day to be 0.25. What is the producers expected profit?
B. $11,450
The variance of sum of two random variables x and y is
D. ( standard deviation of x)^2 + (standard deviation of y)^2 , but only if x and y are Independent
Roll one 10-sided die 12 times. The probability of getting exactly 4 eights in those 12 rolls is given by
D. (12 choose 4)•(1/10)^4 •(9/10)^8
A factory makes silicon chips for use in computers. It is known that about 90% of the chips meet specifications. Every hour a sample of 18 chips is selected at random for testing and the number of chips that meet specifications is recorded. What is the approximate mean and the standard deviation of the number of chips meeting specifications
D. Mean= 16.2 standard deviation= 1.273
In the town of tower hill, the number of cell phones in a household is a random variable W with the following distribution: {table}
E. 0.8