The total amount of protein produced by a dairy cow can be estimated from periodic testing of her milk. The following are the total annual protein production values (lb) for 28 two-year old Holstein cows. Diet, milking procedures, and other conditions were the same for all the animals.
The following parts will create a histogram using 5 classes that describes the data above. Use the column headers when answering the parts:
(a) To determine the width of each class:
What is the difference between the highest and smallest data value (range)?
The width of each class is given by the formula:
WIDTH = INTEGER(range/5) +1
What is the width?
(b) Each class has a lower class (left endpoint) and an upper class (right endpoint). For the FIRST class, the left endpoint is given by the smallest value, and the right endpoint is given by the formula: LEFT ENDPOINT + WIDTH - 1. What is the interval for the first class? What are the remaining classes?
(c) To determine frequency, count the number of data values that fall into each of the five classes from part (b). You should have a total count of 28 in the end.
(d) To determine relative frequency, divide each count by the total (28). As a check, the sum of the relative frequencies is 1 (or 100%).
(e) To create a relative frequency histogram, the class interval goes along the horizontal axis, and the relative frequency (expressed in percentage) goes along the vertical axis. Create a relative frequency histogram. Based on the sketch, describe the distribution (symmetric, skewed left, skewed right).