# Stat homeowrk assignment 1 | Numerical analysis homework help

Homework Assignment #1
Name: __________________________
All calculations should be done in Word using Equation Editor and all charts and graphs should be done in Excel.

1)A manufacturing company produces steel housings for electrical equipment.  The main component part of the housing is a steel trough that is made out of 14-gauge steel coil.  It is produced using a 250-ton progressive punch press with a wipe-down operation that puts two 90-degree forms in a flat steel to make the trough.  The company requires that the width of the trough be between 8.31 inches and 8.43 inches.  Data are collected from a sample of 49 troughs.
8.312   8.343   8.317   8.383   8.348   8.410   8.351   8.373   8.481   8.422   8.476   8.382   8.484   8.403
8.414   8.419   8.385   8.465   8.498   8.447   8.436   8.413   8.489   8.414   8.481   8.415   8.479   8.429
8.458   8.462   8.460   8.444   8.429   8.460   8.412   8.420   8.410   8.405   8.323   8.420   8.396   8.447
8.405   8.439   8.411   8.427   8.420   8.498   8.409

a) Construct a frequency distribution, percentage distribution, cumulative frequency, and a cumulative percentage distribution.

Class Interval Frequency Percentage Cumulative Frequency Cumulative Percentage

b) Construct a frequency distribution histogram, a cumulative frequency histogram, a cumulative percentage polygon plot and a percentage distribution pie chart using excel.

Paste charts from Excel below:

c) What can you conclude about the number of trough that will meet the company’s requirements of troughs being between 8.31 and 8.43 inches wide?

2)If the data set has a mean of 10.0 seconds and a standard deviation of 2.0 seconds, what is the corresponding z-score to the time of 4.0 seconds?

3)Suppose 95% of the data falls between 12.4 and 46.8 units.  Using the empirical rule, give an estimate of the standard deviation.

4)Make a stem and leaf plot of the data, what is the shape of the data
45, 111, 105, 50, 48, 77, 71, 51, 55, 92, 56, 57, 65, 62, 51, 68, 44, 68, 57, 62, 91, 57

Insert stem and leaf plot below:

5)Use the 22 average daily temperatures and the 22 corresponding 22 amounts of energy consumption (kWh) to construct a scatter plot in Excel.  Based on the graph, is there a relationship between the 2 variables?  Identify at least one reason as to why there is or isn’t a relationship.

Average Daily Temp. kWh
29 3637
37 2888
57 2359
74 3704
66 3432
47 2446
28 4463
41 2482
54 2762
68 2288
62 2423
42 3375
26 2661
34 2073
58 2579
72 2858
67 2296
48 2812
33 2433
39 2266
66 3128
71 3286

Paste charts from Excel below:

6)The following data contains the overall miles per gallon of 2009 sedans priced under \$20,000.
27   31   30   28   27   24   29   32   31   27   26   25   26   25   24

a) Compute the mean, median, mode, variance, standard deviation, range, and coefficient of variation, Q1 (Quartile 1) and Q3 (Quartile 3) using Excel.

Cut and paste cells from Excel below:

b) What is the shape of the data?  How do you know?