Question

A professor records the time (in minutes) that it takes 16 students to complete an exam. Compute the SS, the variance, and the standard deviation assuming the 16 students constitute a population and assuming the 16 students constitute a sample. (Round your answers for variance and standard deviation to two decimal places.) 53 39 23 24 32 22 38 47 43 20 44 42 13 31 32 37 (a) the 16 students constitute a population SS Incorrect: Your answer is incorrect. variance Incorrect: Your answer is incorrect. standard deviation Incorrect: Your answer is incorrect. min (b) the 16 students constitute a sample SS variance standard deviation min

Answer 1

Ans:

	xi	(xi-33.75)^2
1	53	370.5625
2	39	27.5625
3	23	115.5625
4	24	95.0625
5	32	3.0625
6	22	138.0625
7	38	18.0625
8	47	175.5625
9	43	85.5625
10	20	189.0625
11	44	105.0625
12	42	68.0625
13	13	430.5625
14	31	7.5625
15	32	3.0625
16	37	10.5625
Total	540	1843
mean	33.75

a)

SS=1843

population variance=1843/16=115.1875

population standard deviation=sqrt(115.1875)=10.7325

b)

SS=1843

sample variance=1843/(16-1)=122.8667

sample standard deviation=sqrt(122.8667)=11.0845