How many permutations of three items can be selected from a group of six? Use the letters A, B, C, D, E, and F to identify the items, and list each of the permutations of items B, D, and F.

A coffee shop owner offers two brands of coffee, Brand "A" and Brand "B". The proportion of clients that prefer Brand "A" is 60%.   Recently, the price of Brand "A" went up. The proportion of clients that buy brand "A" among the first 15 customers that enter the shop after the change in price is an estimator of the current proportion of clients that prefer Brand "A".   Assume that the change in price has no effect on the preference of the clients. Then the mean squared error (MSE) of the estimator is equal to: (Give an answer of the form x.xxx, i.e. with 3 significance digits) (HINT: Carefully read the definition of MSE in Chapter 10 of the text book.)

How many ordered lists are there of three items chosen from four? ordered lists

At a birthday party 34 guests are in attendance and 4 of them are randomly chosen to each receive a $25 gift card. How many ways can the cards be awarded?

Toward the end of a game of Scrabble you hold the letters D,O,G and Q.  You can choose three of these four letters and arrange them in order in how many different ways?