Question

The average number of customers that visited a particular store during the past year is 200 per day and a standard deviation of 25 customers per day. The probability that x>200 is:

Answer 1

0.5

Explanation:

Considering we are given a mean and standard deviation, the distribution of the data is likely to be a normal or Gaussian distribution, i.e. a symmetrical, bell-shaped distribution of probability density, peaked at the mean;

Such a distribution has 0.5 probability each side of the mean;

So, if the mean is 200 then, the probability that the number of customers is greater than 200 (x > 200), according to this mean, is 0.5;

As a normal distribution is symmetrical, this is also the probability of a number of customers less than 200.