Blog

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.

In 2018, a study was conducted that stated that the average commute time to work for Kern County residents was 22.6 minutes. Suppose you were hired to determine if the average commute time is different than it was in 2018. You randomly sample 87 individuals who commute to work from Kern county and you find that their average commute time was 21.6 minutes and you find the sample standard deviation of commute times for those 87 individuals was 3.6 minutes.  Carry out the appropriate hypothesis test at the

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 28 students in his class and their final letter grades are shown below.  Distribution Table of Letter Grades Letter Grade Count/Frequency A 6 B 6 C Left Blank on Purpose D 4 F 1 Total 28 What percentage (relative frequency) of students received a C? Give your answer as a percentage rounded to 2 decimal places (i.e. If the answer is 17.43%, simply type in 17.43)

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 123?   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.

Isabella works for an insurance company and she is the director of the customer service department. One of her main goals is to reduce the wait times that customers experience when they call the department before they are connected to someone that can help them. She recorded all of the wait times that customers experienced in a given month and recorded it in the frequency distribution table below.  Suppose you were to construct a histogram based on this data (starting with the 0-5 minute group on the far left) identify what the overall shape of the data would look like.  Customer Wait Time Breakdown Minutes Spent Waiting Frequency 0 – 5 87 6-10 38 11-15 12 16-20 5 21-25 2 26+ 0  

A business professor was interested in seeing how students had fared on her final exam over the years. She looked back at students who had taken her class over the last 5 years and recorded their exam scores and summarized that information in the table below. Suppose you were to construct a histogram based on this data (starting with 0-9 group on the far left) identify what the overall shape of the data would look like.  Final Exam Breakdown Final Exam Score Frequency 0 – 9 0 10 – 19 1 20 – 29 3 30 – 39 2 40 – 49 4 50 – 59 7 60 – 69 15 70 – 79 56 80 – 89 58 90 – 100 49  

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 Left Blank on Purpose B 9 C 11 D 4 F 3 Total 33 What percentage (relative frequency) of students received an A? Give your answer as a percentage rounded to 2 decimal places (i.e. If the answer is 17.43%, simply type in 17.43)

A fan at a professional football game thought that his team’s quarterback preferred to throw to the right side of the field during games. Over the course of 3 games, he took note on each passing play on whether the quarterback threw the ball to the left or right side of the field. He found that the quarterback threw the football a total of 102 times over the 3 games and 60 of those throws were to the right side of the field while 42 were to the left side of the field. He used this information to conclude that the quarterback preferred to throw the football to the right side of the field.  Based on the situation described above, state whether the ran conducted an observational or an experimental study. Justify your answer.