To find the variance and standard deviation we need to find the mean first:
(18+7+19+14+24)/5=16.4.
To find the variance we subtract the mean from each of the given data values:
1.6, -9.4, 2.6, -2.4, 7.6.
Then we square each value:
2.56, 88.36, 6.76, 5.76, 57.76.
Then we find the average of these to find the population variance, assuming that the given data is the total population:
(2.56, 88.36, 6.76, 5.76, 57.76)/5=161.2/5=32.24. Nearest whole number is 32, nearest tenth is 32.2.
If the data was a random sample then the variance would be 161.2/4=40.3. Nearest whole number is 40.
The population standard deviation is the square root of the population variance=√32.24=5.68 approx. Nearest whole number is 6, nearest tenth is 5.7.
The sample standard deviation is √40.3=6.348. Nearest whole number is 6, nearest tenth is 6.3.