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Practice Test Unit 1

Practice Test Unit 1. 1. What is the probability of landing on heads, when flipping a coin?. What is the probability of rolling a die and landing on 2?. Marcus spins the spinner 50 times and finds that the probability of landing on the letter B

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Practice Test Unit 1

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  1. Practice TestUnit 1

  2. 1 What is the probability of landing on heads, when flipping a coin? What is the probability of rolling a die and landing on 2?

  3. Marcus spins the spinner 50 times and finds that the probability of landing on the letter B is ¼ . He spins the spinner 8 more times, landing on the letter B the first 7 spins. What is the probability of the spinner landing on B on the 8th spin? 1

  4. The graph shows the number of pounds three athletes have lost in a week. How many weeks will it take Mark to lose the same number of pounds that Trey lost in 4 weeks? 2 Trey weight loss 6 pounds One week: Four weeks: 4  6 = 24 pounds Mark weight loss 4 pounds One week: How many weeks to lose 24 pounds? 24  4 = 6 weeks

  5. Find the mean for the graph below. 3

  6. Survey results suggest that 45% of voters support the mayor for re-election. In order to be 95% confident in receiving a majority of the votes, the mayoral campaign conducts a computer survey resulting in the data listed below. 4 Based on the margin of error and simulations, what is the range of percentages of votes the mayor could receive? 0.25 to 0.50

  7. Classify the sampling method for each problem. 5 a. A startup company wants to do a survey to find out if people would produce its product. Company employees conduct the survey by asking 50 of its friends. Convenience Sample b. An apparel company is coming out with a new line of fall clothes. In order to conduct a survey, it uses a computer to randomly select 100 names from its client list. Simple Random Sample

  8. Classify the sampling method for each problem. 5 c. A couple wants to get a dog for their 6 year old son. They want to find out what dogs are considered friendly for kids. So, they visit a dog shelter, which consists of the Irish Settler, Golden Retriever, and Labrador Retriever breeds. Stratified Sample d. A school wants to gauge teacher morale. The school decides to survey every 10th person from their list of teachers. Systematic Sample

  9. A math teacher wants to determine is using a calculator on counting problems will affect the test scores of students. She conducts an experiment to see is if allowing students to use a calculator on a test will affect their scores. What is the null hypothesis? 6 Using a calculator on a test will not affect test scores.

  10. The makers of a light bulb claim that their light bulbs last longer than the leading brand. A researcher tests this claim by finding the mean length of time that 25 bulbs of each brand last. 7 Null Hypothesis: Both brands of light bulbs last the same amount of time. The is no difference in the amount of time both light bulb brands last.

  11. 8 A pharmaceutical company is testing a new drug to see whether it lowers cholesterol in women. They randomly divide 150 volunteers into two groups. The volunteers in each group have their cholesterol monitored for one month to establish a baseline. Then one group is given the drug for a one month period, and the other group is given a placebo for a one month period. The mean change in cholesterol before and after treatment is found for each group. State the null hypothesis for the experiment. Null Hypothesis: The mean change is cholesterol for both groups is the same. There is no difference in the mean change in cholesterol for both groups.

  12. 9 A software company is testing whether a new interface decreases the time it takes to complete a certain task. In a random trial, Group A used the existing interface and Group B used the new one. The times in seconds are given for the members of each group. Null Hypothesis: The time it takes to complete a task is the same for Group A and Group B. There is no difference in the time it takes to complete a task for Group A and Group B. Do you reject the null hypothesis. Use box-and-whisker plots.

  13. 9 A software company is testing whether a new interface decreases the time it takes to complete a certain task. In a random trial, Group A used the existing interface and Group B used the new one. The times in seconds are given for the members of each group. Group A 9 12 12 13 14 14 15 16 16 17 Min Q1 Q3 Max Median14

  14. 9 A software company is testing whether a new interface decreases the time it takes to complete a certain task. In a random trial, Group A used the existing interface and Group B used the new one. The times in seconds are given for the members of each group. Group B 8 9 10 10 10 12 13 13 14 14 Min Q1 Q3 Max Median11

  15. A software company is testing whether a new interface decreases the time it takes to complete a certain task. In a random trial, Group A used the existing interface and Group B used the new one. The times in seconds are given for the members of each group. 9 Group A Group B Yes. The graphs are very different. Do you reject the null hypothesis.

  16. 10 The company claims that its new rubber ball will raise the average bounce height to 5 feet. In a new trial, 9 balls were tested, and the average bounce was 4.5 feet with a standard deviation of 1 foot. Find the z-value. Null Hypothesis The average bounce height will stay the same for the new rubber ball.  = 5 σ = 1 n = 9

  17. 10 Null Hypothesis The medication makes no difference in blood sugar levels.  If |z| > 1.96, then you can reject the null hypothesis with 95% certainty.  If |z| < 1.96, then you do not have enough evidence to reject the null hypothesis. • If |z| = 1.5 < 1.96 So, you do not have enough evidence to reject the null hypothesis.

  18. The data distribution shows the results of tests scores in a math class. If the mean score is 67 and the standard deviation is 4, estimate the proportion of the scores less than 75. 11 The proportion can not be calculated, because the curve is NOT symmetric.

  19. 12 Scores on a test are normally distributed with a mean of 200 and a standard deviation of 12. Find the probability of selecting a student who scored less than 182 or more than 200. Find the standard normal values (z) of 182 and 200. For 182: = –1.5 For 200: = 0

  20. 12 Scores on a test are normally distributed with a mean of 200 and a standard deviation of 12. Find the probability of selecting a student who scored less than 182 or more than 200. Use the table to find the areas under the curve less than z = –1.5 and greater than z = 0. z = –1.5 z = 0 Area = 0.07 Area = 1 – 0.5 = 0.5 Answer Add both shaded areas 0.07 + 0.5 = 0.57 z = 0 z = –1.5 182 200

  21. The graph is a normal distribution with a standard deviation of 6. What is the best estimate of the probability of the shaded area under the curve? 13 Note: Find the probability of the shaded area between 24 and 32. • = 20 • σ = 6 Find the standard normal values (z) of 24 and 32. For x = 24: For x = 32:

  22. The graph is a normal distribution with a standard deviation of 6. What is the best estimate of the probability of the shaded area under the curve? 13 Find the probability of the shaded area between 24 and 32. Use the table to find the areas under the curve for all values less than z. z = 0.67 (close to 0.5) z = 2 Area = 0.98 Area is approximately 0.69 Answer Subtract both shaded areas 0.98 – 0.69 = 0.29

  23. There are 100 eighth graders at Kim’s school. Each eighth grader has the option of participating in basketball, volleyball, or track. How many students chose to participate in all three sports? 14 Basketball Volleyball Answer 16 students participate in all three sports. 11 15 15 16 10 11 17 5 Track

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