Given:
xbar = 20 min
standard deviation = 8 min
total sample = 240
Required:
how many gym members are expected to spend 4 min and 36 min on a treadmill today
Solution:
sd² = (∑(x - xbar)²) / N - 1
there are 42 gym members at 4 minutes and 200 gym members in 36 minutes.