University:
Missouri State University
Course:
MTH 340 | Statistical Methods
Academic year:

2022
Views:

450

Pages:

2
Author:

Eden Robbins

AP Statistics Quiz A-Chapter 18 Name 1. According to Gallup, about 33% of Americans polled said they frequently experience stress in their daily lives. Suppose you are in a class of 45 students. a. What is the probability that no more than 12 students in the class will say that they frequently experience stress in their daily lives? (Make sure to identify the sampling distribution you use and check all necessary conditions.) b. If 20 students in the class said they frequently experience stress in their daily lives, would you be surprised? Explain, and use statistics to support your answer. 2. The average composite ACT score for Ohio students who took the test in 2003 was 21.4. Assume that the standard deviation is 1.05. In a random sample of 25 students who took the exam in 2003, what is the probability that the average composite ACT score is 22 or more? (Make sure to identify the sampling distribution you use and check all necessary conditions.) AP Statistics Quiz C-Chapter 18 Name 1. It is generally believed that nearsightedness affects about 12% of children. A school district gives vision tests to 133 incoming kindergarten children. a. Describe the sampling distribution model for the sample proportion by naming the model and telling its mean and standard deviation. Justify your answer. b. Sketch and clearly label the model. C. What is the probability that in this group over 15% of the children will be found to be nearsighted? 2. Wildlife scientists studying a certain species of frogs know that past records indicate the adults should weigh an average of 118 grams with a standard deviation of 14 grams. The researchers collect a random sample of 50 adult frogs and weigh them. In their sample the mean weight was only 110 grams. One of the scientists is alarmed, fearing that environmental changes may be adversely affecting the frogs. Do you think this sample result is unusually low? Explain.