Probability & Statistics

Question 1

What is most nearly the sample standard deviation of the following data set?

{4,6,9,9}

A. 2.1

B. 2.4

C. 4.2

D. 6.0

Answer 1

Use calculator

make a list

use 1-var stats

its the “Sx”

Question 2

Answer 2

Use calculator

Put the values on L1

Put frequency on L2

Use 1-var stats

choose L1 for list and L2 for frequency.

Question 3

Answer 3

Put x values on L1

Put y values on L2

Use 2-Var Stats

Scroll down and look for the value of “a” as in y=ax+b

Question 4

Answer 4

Probability of no six = (5/6)

probability of four no sixes = (5/6)^4

(5/6*5/6*5/6*5/6) - 1 = 0.52

Question 5

Answer 5

Find the z scores for both 65 and 78

subtract the z(65) from z(78)

Question 6

When do you use the calculator function BinomialCDF?

When do you use the calculator function BinomialPDF?

Answer 6

Use BinomialPDF when you have an exact number: all, half, none, or a specific number x

Use BinomialCDF when you have questions wording similar to:

• No more than, at most, does not exceed.
• less than or fewer than.
• at least, more than, or more, no fewer than X, not less than X.
• Between two numbers (run BinomCDF twice)

Question 7

Answer 7

BinomialPDF function

trials = 4

p(each individual success) = 1/2

Number of successes = 3

Question 8

A fair coin is tossed three times. What is the approximate probability of heads appearing at least one time?

(A) 0.67

(B) 0.75

(C) 0.80

(D) 0.88

Answer 8

Calculate the probability of 3 losses

(1/2)^3

then subtract from 1.

Question 9

Answer 9

Plug list into calculator

1-var stats w/ frequency

Use the standard deviation to find the z score.

Use table to find probability

P(X < 2350) = P(Z < -1.0)

= R(1.0)

= 0.1587

Question 10

Answer 10

Plug into calculator and find Sigma(x)

Question 11

Answer 11

Question 12

Answer 12

Binomial Distribution

number of trials = 20

p(of success) = 0.15

x = 2

use calculator

Question 13

Answer 13

probability of 3 misses

(1/4)(1/4)(1/4) = 1/65

1-(1/64)= 63/64