Richard and his 5 best friends want to see how their 100m dash times compare to the other runners in their district. There are records of all 200 other runners' times so Richard can calculate the population standard deviation. Why would a t-test be better than a z-test in this scenario   Select one: 1. The population is <500 2. The sample standard deviation cannot be calculated 3. The sample size is <30

A large chemistry course took their final exam. The mean was 75 with a standard deviation of 8. What are the exam scores that separate the top and bottom 5 percent of the class (extreme 10%)?                             What are the exams scores that separate the middle 10% of the class (5% on each side of the mean)?                             What proportion of people scored in the A range (90 or above)?                       What proportion of people failed the exam (60 or belo

Kathy and her brother Clay recently ran in a local marathon. The distribution of finishing timefor women was approximately normal with mean 259 minutes and standard deviation 32minutes. The distribution of finishing time for men was approximately normal with mean 242minutes and standard deviation 29 minutes. (a) The finishing time for Clay was 289 minutes. Calculate and interpret the standardized scorefor Clay’s marathon time. Show your work. (b) The finishing time for Kathy was 272 minutes. What proportion of women who ran themarathon had a finishing time less than Kathy’s? Show your work. (c) The standard deviation of finishing time is greater for women than for men. What does thisindicate about the finishing times of the women who ran the marathon compared to thefinishing times of the men who ran the marathon?

If the mean snowfall for Ottawa Ontario Canada is 98 inches per year and the standard deviation is 25 inches what percentage of the time does Ottawa receive less than 125 inches of snow?

The results of a common standardized test used in psychology research is designed so that the population mean is 155 and the standard deviation is 30. A subject earns a score of 194. What is the z-score for this raw score?z-score =

Please don't provide handwriting solution

Konstantinos participates in a bowling league each summer and again each autumn. In Summer 2021, his mean score for the year was 160. For the whole league, the mean score was 158 with a standard deviation of 6. For Autumn 2021, his mean score was 164. The mean for the entire Autumn league was 160 with a standard deviation of 4.5. In which league (summer or autumn) did Konstantinos perform better relative to his peers? please explain your response and round any numeric answers to three (3) decimal places

I wanted to test if the mean Exam 3 score in this course was different than the mean Exam 2 score. I then did a different test than the previous questions. I instead used the 30 students in my course last semester as my sample for Exam 3, and I used a sample of 25 students from this class as my sample for Exam 2. The sample mean score for Exam 2 was 84.0 with a standard deviation of 2.0, and the sample mean score for Exam 3 was 82.0 with a standard deviation of 1.8. What is the t-value used in the 95% confidence interval for the mean difference between Exam 2 and Exam 3? Group of answer choices 2.045 2.064 2.042 2.060

Deanna is the principal at a Midwestern middle school and wants to know the average IQ of all female, seventh grade students.  She does not know anything about what the population distribution looks like.  She took a simple random sample of 31 seventh-grade girls in her school and found the average IQ score in her sample was 105.8 and the standard deviation was 15. Using the sample standard deviation above to estimate the population standard deviation, what is the minimum sample size needed for a 99.5% confidence interval to have a margin of error of no more than 2.3?