Question

Construct a normal probability plot for the following sample of observations on coating thickness for low-viscosity paint.

0.81	0.86	0.88	1.04	1.09	1.13	1.29	1.30
1.48	1.49	1.60	1.63	1.65	1.69	1.75	1.84

Determine the z percentile associated with each sample observation. (Round your answers to two decimal places.)

Sample observation	0.81	0.86	0.88	1.04	1.09	1.13	1.29	1.30
z percentile
Sample observation	1.48	1.49	1.60	1.63	1.65	1.69	1.75	1.84
z percentile

Would you feel comfortable estimating population mean thickness using a method that assumed a normal population distribution?

Yes, the probability plot is reasonably straight.

Yes, the probability plot is not straight.   

No, the probability plot is reasonably straight.

No, the probability plot is not straight.

Answer 1

		(i-0.5)/n	y ordinalte
S.no	x	percentile	z score
1	0.81	0.0313	-1.86
2	0.86	0.0938	-1.32
3	0.88	0.1563	-1.01
4	1.04	0.2188	-0.78
5	1.09	0.2813	-0.58
6	1.13	0.3438	-0.40
7	1.29	0.4063	-0.24
8	1.3	0.4688	-0.08
9	1.48	0.5313	0.08
10	1.49	0.5938	0.24
11	1.6	0.6563	0.40
12	1.63	0.7188	0.58
13	1.65	0.7813	0.78
14	1.69	0.8438	1.01
15	1.75	0.9063	1.32
16	1.84	0.9688	1.86

from above:

observation	0.81	0.86	0.88	1.04	1.09	1.13	1.29	1.3
z percentile	-1.86	-1.32	-1.01	-0.78	-0.58	-0.40	-0.24	-0.08
observation	1.48	1.49	1.6	1.63	1.65	1.69	1.75	1.84
z percentile	0.08	0.24	0.40	0.58	0.78	1.01	1.32	1.86

Yes, the probability plot is reasonably straight.