Probability Review

Probability Distribution

100

What is the name of a variable whose value is determined by the outcomes of random events? A. Normal Distribution B. Random Variable C. Histogram D. Discrete Random Variable

B. Random Variable

200

What is the name of a variable that can take on a countable number of distinct values? A. Continuous Random Variable B. Algebraic Variable C. Discrete Random Variable D. Histogram

C. Discrete Random Variable

300

Which of the following is an example of a discrete random variable? A. the height in inches of a student in the classroom B. the time it takes in minutes to get to Walmart C. the temperature in degree Celsius outside D. the number of students who own a dog

D. the number of students who own a dog

400

X= the number of hours a student in this class spends watching TV; 2 students watch 0 hours, 7 students watch 1 hour, 15 students watch 2 hours, 5 students watch 3 hours, and 3 students watch 5 hours. What is the probability that a randomly selected student from the class watches 2 hours? A. 15/32; B. 7/32; C. 9/32; D. 13/52

A. 15/32

500

Given the following probability distribution: P(X=0) = 1/12; P(X=1) = 1/12; P(X=2) = 3/12; P(X=3) = 5/12; P(X=4) = 2/12; Find P(X≥2). A. 5/12; B. 5/6; C. 1/6; D. 7/12

B. 5/6

Binomial Distribution

100

What type of variables are associated with the Binomial Distribution? A. Continuous Random Variables B. Algebraic Variables C. Discrete Random Variables D. Standard Normal Distributions

C. Discrete Random Variables

200

Find P(X=3) using the formula for P(X=k) for a Binomial Distribution, given that n=56 and p=0.12. A. 0.057; B. 0.051; C. 0.055; D. 0.543

C. 0.055

300

Given that n=6 and p=0.76, find P(X≥4). A. 0.003; B. 0.846; C. 0.234; D. 0.288

B. 0.846

400

Suppose that 15% of students at ECHS play sports. If there are 32 students in 1st period, what is the probability that 4 students in 1st period play sports? A. 14; B. 0.19; C. 0.14; D. 19

B. 0.19

500

Suppose we throw the single die 5 times. What is the probability that the die lands on "2" three times? A. 0.032; B. 0.161; C. 0.402; D. 0.401

A. 0.032

Normal Distribution

100

What is the normal curve's shape? A. Square-shaped B. Right-skewed C. Left-skewed D. Bell-shaped

D. Bell-shaped

200

What percent of data is located at or below x ̅ + σ? A. 84%; B. 0.84; C. 16%; D. 0.16

A. 84%

300

For a randomly selected x-value from the Normal Distribution, find P(x ̅ - 2σ ≤ x ≤ x ̅ +3σ). A. 97.35%; B. 0.95; C. 0.9735; D. 95%

C. 0.9735

400

Suppose the Math EOCT scores of 500 students at ECHS are normally distributed with a mean of 85 and a standard deviation of 9. About how many students have scores between 67 and 94? A. 170; B. 408; C. 340; D. 475

B. 408

500

Suppose the Math EOCT scores of 500 students at ECHS are normally distributed with a mean of 85 and a standard deviation of 9. About how many students have scores below 103? A. 170; B. 408; C. 340; D. 488

D. 488

Standard Normal Distribuiton

100

What is the mean and standard deviation of a Standard Normal Distribution? A. mean= 100, σ=5; B. mean= 0, σ=1; C. mean= 1, σ=0; D. mean= 100, σ=10

B. mean=0, σ=1

200

Suppose the mean of a normal distribution is 65 and the standard deviation of the distribution is 2. Calculate the z-score for an x-value of 73. A. 6; B. 10; C. 4; D. 3

C. 4

300

Find P(z≤-2.8) using the z-score table. A. 0.9974; B. 0.0026; C. 0.9981; D. 0.0019

B. 0.0026

400

Suppose that data set is normally distributed with a mean of 57 and standard deviation of 8. Find P(x≤70) using the z-score table. A. 0.9332; B. 0.0548; C. 0.9452; D. 0.9554

C. 0.9452

500

Suppose that data set is normally distributed with a mean of 34 and standard deviation of 5. Find P(x≤32) using the z-score table. A. 0.3446; B. 0.6554; C. 0.3085; D. 0.0808

A. 0.3446

Normal Approximation and Hypothesis Testing

100

What are the conditions a Binomial Distribution must meet to be approximated by a Normal Distribution? A. np≤5, n(1-p)≤5; B. np<5, n(1-p)<5; C. np>5, n(1-p)>5; D. np≥5, n(1-p)≥5

D. np≥5 n(1-p)≥5

200

If we are to approximate a Binomial Distribution with a Normal Distribution, what would the mean and standard deviation of the Normal Distribution be? A. mean= np, standard deviation= √(np(1-p)); B. mean= √(np(1-p)), standard deviation= np; C. mean=n(1-p), standard deviation= √(np); D. mean=np, standard deviation=np(1-p)

A. mean= np, standard deviation= √(np(1-p))

300

It is appropriate to reject a statistical hypothesis if the probability of obtaining the desired results is... A. small, less than 0.05; B. large, more than 0.5; C. large, more than 0.05; D. small, less than 0.5

A. small, less than 0.05

400

Using the fact that 12% of people wear contact lenses. If ECHS had 1075 students, what would be the probability that at least 151 students wear contract lenses? A. about 0.075; B. about 0.034; C. about 0.025; D. about 0.045

C. about 0.025

500

You read an article that claims that 44% of students at ECHS are on Twitter. You want to test the findings, so you survey 60 students at ECHS and find that 21 of them are on Twitter. Should you reject your findings? A. Yes, P(x≤21)=1.4; B. No, P(x≤21)=0.5612; C. Yes, P(x≤21)=0.0808; D. No, P(x≤21)=0.0808

D. No, P(x≤21)=0.0808