Question

Construct a normal probability plot for the following sample of observations on coating thickness for low-viscosity paint. 0.83 0.89 0.90 1.04 1.08 1.11 1.29 1.32 1.48 1.50 1.57 1.64 1.66 1.70 1.74 1.84 Determine the z percentile associated with each sample observation. (Round your answers to two decimal places.) Sample observation 0.83 0.89 0.90 1.04 1.08 1.11 1.29 1.32 z percentile Sample observation 1.48 1.50 1,571.64 1.66 1.701.74 1.84 z percentiie Choose the plot that best represents the normal probability plot for the sample of observations. thickness thickness .2 1.2 1.0 0.8 1.2 0.8 O -2 0 thickness thickness 1.8 1.6 1.4 1.2 1.2 1.O 0.8 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

a)

We are given x values

Calculating z values and then z percentiles

VALUE	Z SCORE	Z Percentile	Z Percentile above the x score
0.83	-1.54355	0.061348881	0.938651119
0.89	-1.36523	0.086090012	0.913909988
0.9	-1.33551	0.090854246	0.909145754
1.04	-0.91944	0.178932158	0.821067842
1.08	-0.80056	0.211691807	0.788308193
1.11	-0.71141	0.238416092	0.761583908
1.29	-0.17646	0.429966833	0.570033167
1.32	-0.0873	0.465216299	0.534783701
1.48	0.388209	0.651069289	0.348930711
1.5	0.447648	0.672796237	0.327203763
1.57	0.655683	0.743985956	0.256014044
1.64	0.863718	0.806128711	0.193871289
1.66	0.923157	0.822037338	0.177962662
1.7	1.042035	0.85130216	0.14869784
1.74	1.160912	0.877161133	0.122838867
1.84	1.458105	0.927594244	0.072405756
	Mean	1.349375
	SD	0.336481178

Plotting the x values and the z scores

C0 VALUE 865857454453182 331300732343183 202886596041583 332468087387415 4214605004815310 55454432667109 3659016787533208 331017884562465 5139871034689014 10000000000111

Yes the probability plot is reasonably straight