Lesson 5.1 Checkpoint

Choose a person aged 19 to 25 years at random and ask, “In the past seven days, how many times did you go to an exercise or fitness center or work out?” Call the response Y for short. Based on a large sample survey, here is a probability model for the answer you will get.

Show that this is a valid probability distribution.

(LT 5.1.1 #1)

• Valid

• Invalid, doesn't add up to 1

• Invalid, not all between 0 and 1

• Valid, because they don't add up to 1

Choose a person aged 19 to 25 years at random and ask, “In the past seven days, how many times did you go to an exercise or fitness center or work out?” Call the response Y for short. Based on a large sample survey, here is a probability model for the answer you will get.

Describe the event Y < 3 in words.

(LT 5.1.2 #1)

• A randomly chosen 19 to 25 year old has gone to a fitness center or worked out 3 or fewer days

• A randomly chosen 19 to 25 year old has gone to a fitness center or worked out fewer than 3 days

• A randomly chosen 19 to 25 year old has gone to a fitness center or worked out 3 or more days

• A randomly chosen 19 to 25 year old has gone to a fitness center or worked out more than 3 days

Choose a person aged 19 to 25 years at random and ask, “In the past seven days, how many times did you go to an exercise or fitness center or work out?” Call the response Y for short. Based on a large sample survey, here is a probability model for the answer you will get.

What is the P(Y < 3)?

(LT 5.1.2 #2)

• 0.68

• 0.05

• 0.07

• 0.80

Classify each of the following random variables as discrete or continuous.

H = the number of homework problems assigned by your statistics teacher on a randomly selected class day

(LT 5.1.3 #1)

• Discrete

• Continuous

Classify each of the following random variables as discrete or continuous.

R = the temperature of the turkey meat in a randomly chosen location in a cooked turkey

(LT 5.1.3 #2)

• Discrete

• Continuous

Classify each of the following random variables as discrete or continuous.

X = the reported score of a randomly selected senior at your school on the SAT Math test

(LT 5.1.3 #3)

• Discrete

• Continuous

The following probability distribution is for the random variable X = number of mice caught in traps during a single night in a small apartment building.

Is X a discrete or a continuous random variable? Explain.

(LT 5.1.3 #4)

• Discrete, because it has a fixed set of values with gaps.

• Continuous, because it can take any value in an interval.

The following probability distribution is for the random variable X = number of mice caught in traps during a single night in a small apartment building.

Is the probability distribution of X is valid?

(LT 5.1.1 #2)

• Valid

• Invalid, doesn't add up to 1

• Invalid, not all between 0 and 1

The following probability distribution is for the random variable X = number of mice caught in traps during a single night in a small apartment building.

Express the event “trapping at least 1 mouse” in terms of X and find its probability.

(LT 5.1.2 #3)

• P ( X ≥ 1) = 0.88

• P ( X ≤ 1) = 0.22

• P ( X > 1) = 0.68

• P ( X < 1) = 0.12