Notes for Homework 4, due September 16

Notes on contingency tables

In Excel: the sum of a row will be of the form
=sum(a1:c1) where the letters are the changing indices

The sum of a column will be
=sum(a1:a5) where the numbers are the changing indices

Notes on the Central Limit Theorem

In Excel: In my version of Excel, the function that gives you the proportion less than a z-score is

=norm.dist(x, mean, standard_dev, cumulative)

The cumulative value should be 1 always.

If we are doing a Central Limit z-score based on the average of a sample, the instruction is changed as follows. 

=norm.dist(x, mean, standard_dev/sqrt(n), cumulative)

where n is the size of the sample.

Notes on probabilities of independent trials

In Excel: Again, different versions of Excel have different spelling of functions, and in my version the function is

=binom.dist(r, n, p, cumulative)

If cumulative = 0, you get the value of exactly r successes in n trials.

If cumulative = 1, you get the value of at least r successes in n trials.