Kelsie works at a bicycle shop as a salesperson. she records the number of bicycles she sells daily. here is the probability distribution of b = the number of bicycles kelsie sells on a randomly selected day, and t the time she spends filling out daily sales reports. 2 b = # of bicycles sold t = time (minutes) probability 40 20 10 0.05 0.15 0.50 0.30

a) calculate e(b)
b) calculate the mean time she spends filling out daily reports.
c) calculate the standard deviation for both random variables.

Now max recorded the heights of 500 male humans. he found that the heights were normally distributed around a mean of 177 centimeters. which statements about max’s data must be true? a) the median of max’s data is 250 b) more than half of the data points max recorded were 177 centimeters. c) a data point chosen at random is as likely to be above the mean as it is to be below the mean. d) every height within three standard deviations of the mean is equally likely to be chosen if a data point is selected at random.