Assume we know the distribution of the population is normal assume that the sample mean and standard deviation are good approximations for the...

Assume we know the distribution of the population is normal assume that the sample mean and standard deviation are good approximations for the population mean and standard deviation. Suppose we choose an arbitrary subject from our study and look at their contact time x with the advertising medium we have chosen What is:

(a) P ( x < 2 ) ?

(b) P ( x > 10 ) ?

(c) P ( 1 < x < 5 )?

Standard deviation (σ): 5.2546540218067

Arithmetic mean (μ): 7.5333333333333

Hours collected on subjects:

3 11 2 4 3 3 5.5 16 7.5 15 6 8 17 20 1 3 9 14 3 13 3 5 1.5 3 3 7 5.25 9.25 15

10

Mean ‘µ’ = 7.5333, Standard deviation ‘ σ’ = 2.25465Standard normal variable ‘Z’ = [x - µ]/σ1) P [ x &lt; 2 ] = p [ Z &lt; (2 – 7.5333) / 2.25465 ]= p [Z &lt; -2.4542]= 0.0090...