Statistics and Probability Answers

out of 2000 families with 4 children, how many would you expect to have 1 or 2 girls, given that the probability of a male birth is 0.5____

Evaluate (x-2)!(y-4) if x=6 and y=9

When you toss 5 coins once, if the number of head(s) is the random variable define on the resulting sample space. What is the set of random variable resulting from this experiment?

How many different outcomes can we expect if we flip the coin 5 times?

While in a newsagents the probability that Ed buys a newspaper is 0.8
In the same newsagents the probability that Ed independently buys a magazine is 0.3
Work out the probability that Ed buys at least a newspaper or a magazine in the same newsagents. Include diagram

Suppose a biological cell contains 400 genes. When treated radioactively the probability that
a gene will change into mutant gene is 0.006 and is independent of the other genes. What is
the approximate probability that there are at most 4 mutant genes after the treatment?

A fruit processing unit produces canned fruit juice with a mean weight of 1 kg. and variance
of 0.020 kg. The cans are packed in boxes each containing 100 cans. Assuming that the
weights of individuals cans are statistically independent find the probability that the weight of
a box is between 99 kg. and 101.5 kg.

The manufacturer of a popular brand of TV knows from his past experience that the
probability of his TV set failing to work properly during the warranty period is 0.04. Find the
probability that in a sample of 25 sold TV sets selected at random, 6 or less TV sets will be
failing to work properly during the warranty period. Use both the binomial and Poisson rule
and compare the results.

The number of gamma rays emitted per second by a certain
radioactive substance is a random variable having Poisson distribution
with
  5.8. If a recording instrument becomes inoperative when
there are more than 12 rays per second, what is the probability that this
instrument becomes inoperative during any given secondHa 4

The following table shows the pesticide residue levels (ppb) in blood samples from
four populations of human subjects. Use the Kruskal-Wallis test to test at the
0:01 level of signicance the null hypothesis that there is no dierence among the
populations with respect to median level of pesticide residue.
Population
A B C D
10 4 15 7
37 35 5 11
12 32 10 10
31 19 12 8
11 33 6 2
9 18 6 5
44 11 9 4
12 7 11 5
15 32 9 2
42 17 14 6
23 8 15 3