Question

USING EXCEL

Now your task is to plot the cumulative probability density function with the information given in number 2. First, open Worksheet #3. Then enter “=” in cell A17 of your new worksheet and then click on cell A17 of your second worksheet and hit return. Then copy cell A17 down the A column as before.

              Next, you’re to compute the cumulative probabilities for x = 0, 1, 2, …. 20, beginning in cell B17 and ending in cell B37, using BINOM.DIST, of course.

              Once you’ve done that, prepare a histogram-like graph of the cumulative probability distribution, as you did in question 2. Label the vertical axis “P(X ≤ x); the horizontal axis, “x = 0 1 2 3 4 5 … 20”; and the graph, “Exercise 4, #3 Discrete CDF (p = ,35)”. (You’ll want to add in some “major” horizontal gridlines as well.)

              Finally, below your graph, please answer the following question: why do cumulative probability functions of discrete variables take on this stepwise form?

Answer 1

Solution:-

We have given that, number of trials are n= 20 and probability of success p= 0.35.

By using command " =BINOM.DIST(x,n,p,TRUE()) " we have have to find cumulative probability for x=0,1,2,......,20 as follows With graph of cumulative probabilities.

The discrete variable takes an integer values. Therefore, the probability function of discrete variable takes stepwise form.