Instructions:
Below you will find questions. Please use the provided data to complete the tasks and to answer the questions.
- Produce the probability histogram (probability distribution plot) of each of the following and state if the distribution is symmetric, skewed to the left, or skewed to the right.
- The binomial distribution with n = 20 and p = 0.2.
- The binomial distribution with n = 30 and p = 0.48
- The binomial distribution with n = 15 and p = 0.8.
- Suppose X is a binomial random variable with n = 35 and p = 0.67.
- What is the probability that X is exactly 20?
- What is the probability that X is at most 27?
- What is the probability that X is at least 15?
Below you will find questions. Please use the provided data to complete the tasks and to answer the questions.
- For the standard normal distribution, Z, find the proportion (percentage) of observations that satisfies each of the following statements. In each case, use a graph of the Normal curve and shade the area under the curve that is the answer to the question.
- Values of z larger than 2.33.
- Between z = −1.50 and z = 1.18.
- Values of z less than 1.19.
- A set of final examination grades in an introductory statistics course was found to be normally distributed with a mean of 77 and a standard deviation of 8. For each of the following products, a normal distribution plot shows the appropriate shaded area.
- What percentage of students scored lower than 70 on this exam?
- What percentage of students scored between 81 and 89?
- What percentage of students scored higher than 90 on this exam?
- What is the 80th percentile of scores?
- What is the 95th percentile of score?