A list of numbers is as shown below
70, 75, 80, 85, 90, 105, 105, 130, 130, 130
It shows the times in seconds which it took for each of 10 school children to run a distance of 400kilometers. If the standard deviation of the 10 running times is 22.4, how many running times are more than 1 standard deviation below the mean of the 10 running times?
a) One
b) Two
c) Three
d) Four
e) Five
Pls pls pls help. Thanks in advance.
70, 75, 80, 85, 90, 105, 105, 130, 130, 130
It shows the times in seconds which it took for each of 10 school children to run a distance of 400kilometers. If the standard deviation of the 10 running times is 22.4, how many running times are more than 1 standard deviation below the mean of the 10 running times?
a) One
b) Two
c) Three
d) Four
e) Five
Pls pls pls help. Thanks in advance.
