The number of column inches of classified advertisements appearing on Mondays in a certain daily newspaper is normally distributed with population mean of 320 and population standard deviation of 20 inches. For a randomly chosen Monday, what is the probability there will be between 280 and 360 column inches of classified advertisement?

The probability there will be between 280 and 360 column inches of classified advertisement

P(280≤X≤360) = P(-2≤Z≤2) = 0.9544

Step-by-step explanation:

Step(i):-

Given that the mean  the population = 320

The standard deviation of the Population = 20

Let 'X' be the random variable in a normal distribution

Let 'X' = 280

Let 'X' = 360

Step(iii):-

The probability there will be between 280 and 360 column inches of classified advertisement

P(280≤X≤360) = P(-2≤Z≤2)

                        = P(z≤2) -P(z≤-2)

                       = P(z≤2)+P(z≤2)

                      = 2P(z≤2)

                     = 2×0.4772     ( from normal table)

                    = 0.9544

£56

step-by-step explanation: