# Audrey Allen

University of Massachusetts Global

Statistics

Statistics teacher | Tutor for 6 years

I hold a degree in Statistics from the University of Massachusetts Global. With a passion for numbers and data analysis, I specialize in simplifying complex statistical concepts for students. My goal is to empower learners with the skills and confidence needed to excel in mathematics and beyond. Through personalized instruction and real-world examples, I foster a supportive learning environment where students can thrive. Let's embark on a journey of discovery together, where every question is an opportunity to learn and grow.

## Questions

- The heights of males in a certain country are normally distributed with a mean of 70.2 inches and a standard deviation of 4.2 inches. What is the probability that a randomly chosen male is under the height of 65 inches?
- What happens to the confidence interval if you increase the confidence level?
- A jar contains 125 marbles. Given 6% of the marbles are green, 6% of the marbles are blue, and the rest are red, how many red marbles are in the jar?
- A random sample of 40 tea drinkers scores much lower on a stress scale than a random sample of those who do not drink tea. Does drinking tea lower stress?
- What the difference between continuous and discrete variations?
- An exam has two parts. Raul has probability .9 of answering a question from part A correctly and .7 of answering a question from part B correctly. What is the probability that Raul's grade is greater than 75%?
- At a football game, a researcher randomly asks 100 people to name their favorite sport. Is this a biased sample?
- The mean IQ score of statistics professors is less than 119. The significance level is 0.05. What is the null hypothesis (H0) and alternative hypothesis (H1)?
- How do you find the standard deviation of 5.6, 5.2, 4.6, 4.9, 5.7, 6.4?
- Can a random variable with a non-continuous cumulative density function have a probability density function?
- What does it mean when a hypothesis is statistically significant?
- Why can't a confidence level be 100%?
- A wholesaler sells goods to hundreds of retailers and knows both the sales of its own products and the total sales of similar goods at each retailer. How can the wholesaler determine if its goods are selling significantly better than competing goods?
- The mean a person gets to work is 29.7 minutes. If the standard deviation is 6 minutes, within what limits would you expect approx 68% of the times to fall? Assume the distribution is approx bell shaped.
- Katie must take five exams in a math class. If her scores on the first four exams are 76, 74, 90, and 88, what score must Katie get on the fifth exam for her overall mean to be at least 90?
- What is the mean, median, and mode of 45, 50, 47, 52, 53, 45, 51?
- What is the z-score of sample X, if #n = 64, mu= 56, SD =20, and E[X] =320#?
- What is the mean, median, mode, and range of 1.1, 0, 3,2.8 ,4.6?
- What is the z-score of sample X, if #n = 144, mu= 41, St. Dev. =120, and E[X] =63#?
- Suppose that 40% of adult email users say "Yes." A polling firm contacts an SRS of 1500 people chosen from this population. If the sample were repeated many times, what would be the range of sample proportions who say "Yes"?