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*** A die is rolled 6 times (a) What is the chance of obtaining exactly 1 six? (

ID: 3326878 • Letter: #

Question

*** A die is rolled 6 times

(a) What is the chance of obtaining exactly 1 six?

(b) What is the chance of obtaining six first and then not six?

(c) What is the chance of obtaining at least 1 six?

*** Complete the following table for the tossing of an unbiased coin. Use the square root law.

Number of tosses

Number of tails

Expected value |      SE

Percent of tails

Expected value |      SE

100

50 |          2

50% | 2%

2,500

| 0.4%

10,000

1,000,000

Does it confirm the law of averages?

*** You gamble 100 times on the tosse of a coin. If it lands heads, you win $1. If it lands tails, you lose $1. Your net gain will be around ______, give or take _____ or so. Use the box model.

Number of tosses

Number of tails

Expected value |      SE

Percent of tails

Expected value |      SE

100

50 |          2

50% | 2%

2,500

| 0.4%

10,000

1,000,000

Explanation / Answer

Assuming that the die is fair.

So the probability of obtaining a 6 on any roll of die is 1/6.

Modeling this as a Binomial distribution:

(a)

Probability of obtaining exactly one 6 is:

P = 6C1*p1*(1-p)6-1

Putting values:

P = 6C1*(1/6)1*(1-(1/6))5

Solving we get:

P = 0.402

(b)

Probability of obtaining a 6 on the first roll and not obtaining a 6 in the remaining rolls is:

P = (1/6)*(5/6)5 = 0.067

(c)

Probability of obtaining atleast one 6 = 1 - Probability of not obtaining any 6

Probability of not obtaining any 6 = (5/6)6 = 0.335

So,

Probability of obtaining atleast one 6 = 1-0.335 = 0.665

Hope this helps !