DT1141: A T.D. is Interested in Whether Constituents Favour Shorter Opening Hours: Statistics Assignment, NUI

Assignment Questions:

Q1. For each of the following data sets classify the data by the most appropriate data type and scale of measurement.

1. The breakdown of the number of Leaving Cert students throughout Ireland taking each subject for the Leaving Cert examination.
2. The diameter of 30 moulded components measured at Incoming Inspection.
3. Your ranking preference of 5 Chocolate bars.
4. The ambient temperature recorded hourly in a Cleanroom.

Q2. A T.D. is interested in whether constituents favour shorter opening hours for pubs in Ireland. Her staff reports that letters on the issue have been received from 361 constituents and that 283 of these are in favour of shorter opening hours. Identify the population, sample, unit, variable measured, and statistic.

Q3. The following is a breakdown of a sample 100 length dimensions of a moulded component taken from a day’s production at an Injection Moulding plant.

1. Show the relative frequency distribution
2. Show the percent frequency distribution
3.  Show the cumulative frequency distribution.
4.  Show the relative cumulative frequency distribution.
5.  What proportion of parts is between 40mm and 59mm?
6.  What proportion of parts is less than 80mm?
7. What proportion of parts is 70mm or greater?
8. Represent this data graphically, using an appropriate chart

Q4. A molded component is manufactured on two production lines, Line A and Line B. The Target dimension for the component is 20mm +/- 3mm.

Consider the following table of results for a sample of 11 components taken from each line.

• Calculate the mean for both datasets.
• Calculate the standard deviation & variance for both datasets.
• Based on your results above, would you have any preference on which line you would use for manufacturing? Justify your answer.

Note: Ensure to show how to mean, st. dev. & variance was calculated for the above

Q6. Below are datasets from two Production lines that manufacture stainless steel Stents.

The Target Wall-Thickness for a Stent is 120 microns +/- 10 microns [Lower Spec Limit = 110 microns, Upper Spec Limit = 130 microns]

Line A

Line B

• Compare the following data sets by creating two box plots by hand.
• Comment on your results.