Cumulative Exam — Cumulative exam Answers

A survey of high schools offering honors classes to ninth graders reveals that 38% of the high schools offer no honors classes, 12% offer one honors class, 25% offer two honors classes, 20% offer three honors classes, and 5% offer four honors classes.A high school is selected at random. What is the probability that it offers an even number of honors classes?

A security alarm requires a four-digit code. The code can use the digits 0–9 and the digits cannot be repeated.What is the approximate probability that the code only contains odd numbers?

Becky and Carla take an advanced yoga class. Becky can hold 29% of her poses for over a minute, while Carla can hold 35% of her poses for over a minute. Suppose each yoga student is asked to hold 50 poses. Let B = the proportion of poses Becky can hold for over a minute and C = the proportion of poses Carla can hold for over a minute. What is the probability that Becky’s proportion of poses held for over a minute is greater than Carla’s?Find the z-table here.

A teacher has a large container of blue, red, and green beads. She reports to the students that the proportion of blue beads in the container is 0.30. The students feel the proportion of blue beads is lower than 0.30. A student randomly selects 60 beads and finds that 12 of the beads are blue. The P-value for the test of the hypotheses, H0:p=0.30 and Ha:p<0.30, is 0.045. What is the correct interpretation of this value?

The daily temperatures in fall and winter months in Virginia have a mean of 62o F. A meteorologist in southwest Virginia believes the mean temperature is colder in this area. The meteorologist takes a random sample of 30 daily temperatures from the fall and winter months over the last five years in southwest Virginia. The mean temperature for the sample is 59oF with a standard deviation of 6.21oF. The meteorologist conducts a one-sample t-test for and calculates a P-value of 0.007.

In a large high school, 18% of sophomores and 67% of seniors have part-time jobs. Suppose random samples of 32 sophomores and 31 seniors from this high school are asked if they have a part-time job. Let and be the sample proportions of sophomores and seniors, respectively, who have part-time jobs.Which of the following is the correct shape and justification of the sampling distribution of ?

A biologist wants to determine if different temperatures (15oC, 25oC, or 35oC) and amounts of sunlight (partial or full) will affect the growth of plants. He will test each combination of temperature and sunlight by randomly assigning 15 plants to each of the combinations.What type of sampling is described in this study?

A school administrator claims that 85% of the students at his large school plan to attend college after graduation. The statistics teacher at this school selects a random sample of 50 students from this school and finds that 76% of them plan to attend college after graduation. The administrator would like to know if the data provide convincing evidence that the true proportion of all students from this school who plan to attend college after graduation is less than 85%. What are the values of the test statistic and P-value for this test?Find the z-table here.

Some randomly selected high school students were asked to name their favorite sport to watch. The table displays the distribution of results.What is the probability that a student chose football given that they like watching sports?

Two students created a game of dice. They determined that each roll would add the value of the die if it was an odd number. If the roll was even, it would subtract the value of the die. (For example, a roll of 2 would subtract two points, but a roll of 3 would add three points.) What is the expected value for this game?