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A professor at a local community college decided to try out a new lecture format for his statistics class, and he was curious how well students performed using this new format. So the professor decided to record every student’s final grade at the end of the semester to determine how effective this new lecture format was. There were 33 students in his class and their final letter grades are shown below.  Distribution Table of Letter Grades Letter Grade Count/Frequency A 8 B 8 C 10 D 4 F 3 What percentage of students passed the class with a ‘C’ or better? (Cumulative Relative Frequency) Give your answer as a percentage rounded to 2 decimal places (i.e. If the answer is 17.43%, simply type in 17.43)

Consider a town where the average age of all individuals is 35.6 years old with a standard deviation of 13.7 years. Suppose you were to randomly select 50 individuals from this town as part of a study.  What is the probability that the average age of the 50 individuals in your study would be less than 40 years old or greater than 30 years old?

A recent study was conducted and it found that IQ’s are normally distributed with a mean of 100 and a standard deviation of 15. Use this information to find the following value below.  What IQ score would represent the 93rd percentile?   Make sure to write your answer as a decimal rounded to 3 decimal places. For example, if you thought the answer was 123.4567 then you would type in 123.457.

A recent study was conducted and it found that IQ’s are normally distributed with a mean of 100 and a standard deviation of 15. Use this information to find the following value below.  What IQ score would represent the 33rd percentile?   Make sure to write your answer as a decimal rounded to 3 decimal places. For example, if you thought the answer was 123.4567 then you would type in 123.457.

Suppose a study was conducted of community colleges in California to determine the average cost of tuition for in-state students. The study consisted of 45 community colleges from California. Based on the sample data, the average tuition was $1,440 and the sample standard deviation was $267. Use this information to construct and interpret a 92% confidence interval for the true average tuition of all California community colleges.    Make sure to address the following in your response: Check any and all relevant assumptions and state how you determined whether or not they were satisfied (Be as specific as possible) Make sure to type your confidence interval in an interval format with each bound rounded to the nearest whole number.  Make sure to include an interpretation in context of the given problem  

A recent study was conducted and it found that IQ’s are normally distributed with a mean of 100 and a standard deviation of 15. Use this information to find the following probability.  What is the probability that a randomly selected individual would have an IQ of more than 103?   Make sure to write your answer as a decimal rounded to 3 decimal places. For example, if you thought the answer was 23.173% then you would type in 0.232.

A recent study was conducted and it found that IQ’s are normally distributed with a mean of 100 and a standard deviation of 15. Use this information to find the following probability.  What is the probability that a randomly selected individual would have an IQ between 91 and 111?   Make sure to write your answer as a decimal rounded to 3 decimal places. For example, if you thought the answer was 23.173% then you would type in 0.232.

IQ scores are normally distributed with a mean of 100 and a standard deviation of 15. Use this information to answer the following question. What is the probability that a randomly selected person will have an IQ score of at least 86? Make sure to type in your answer as a decimal rounded to 3 decimal places. For example, if you thought the answer was 0.54321 then you would type in 0.543.

Suppose you construct a 90% confidence interval for the true population mean GPA of students at Taft College. If all of the sample values remained constant and you increased the confidence level, what would happen to the width of your confidence interval?

A recent study was conducted and it found that IQ’s are normally distributed with a mean of 100 and a standard deviation of 15. Use this information to find the following probability.  What is the probability that a randomly selected individual would have an IQ of at least 95?   Make sure to write your answer as a decimal rounded to 3 decimal places. For example, if you thought the answer was 23.173% then you would type in 0.232.