Question

1.If p is the probability of success of a binomial experiment, then the probability of failure is -p.

true or false

2.A sample of 4900 cases is drawn at random from an infinitely large population. The standard deviation of the population is 10. The standard error of the mean is

.1/5

.1/7

.3/7

.1/6

chose correct answer and why

Answer 1

solution:

Question 1.

Answer: False.

Explanation : For binomial distribution, If p is the probability of success of a binomial experiment, then the probability of failure is 1-p. Also we know that probability cannot be negative. If p is probability of succes means p is positive. It implies that -p will be negative . So -p cannot be probability.

Question 2.

Answer: 1/7

Explanation : We have for example in hand, sample size n = 4900 and population standard deviation is sd = 10.

As sample size n = 4900 is large then we have from Central Limit theorem (CLT) that sample mean follows Normal distribution with standard error of mean is (population sd) / sqrt(n).

Hence standard error of mean = 10 / sqrt (4900) = 10 / 70 = 1 / 7.

Hence answer is 1/7.