175 Answered Questions for the topic Standard Deviation
How many days did it take the patient to recover?
If the recovery time for a surgery is normally distributed with a mean of 6.1 days and a standard deviation of 2.5 days. And the z-score for a recovery time is -1.45, how many days did the patient... more
Julio observed that customer satisfaction ratings are normally distributed. If the 33rd percentile is 6.775, and the 65th percentile is 7.394 on a scale from 0-10 find the mean and standard deviation
When dragons on planet Pern lay eggs, the eggs are either green or yellow. The biologists have observed over the years that 32% of the eggs are yellow, and the rest green.
When dragons on planet Pern lay eggs, the eggs are either green or yellow. The biologists have observed over the years that 32% of the eggs are yellow, and the rest green. Next spring the lead... more
What is +/- 2 SEM? How would I calculate that? The standard error is 2.786, the standard deviation is 6.229, and the mean is 42.6.
what percent of these differ from the population mean(nomal distribution)
if a set of observations is normally distributed, what percent of these differ from the population mean by more than 0.96σ, where σ is the population standard deviation.
How do you calculate the confidence intervals for a population mean with only the sample mean and sample standard deviation?
I have a random sample and need to calculate the 95% confidence interval for the population mean(sample mean = 1076sample standard deviation = 80.61sample size is n=5)
Question about average thickness, standard deviation and probability distribution
Each manufacturer of sliced bread has to choose how thin to slice their bread. It turns out that sliced bread in the US has an average thickness (μ) of 9.2mm, a standard deviation (σ) of 2.5mm, and... more
what is the standard deviation of this?
what is the standard deviation of the number of dart throws I have to make until I get a bulls-eye (assuming my chances of making a bulls-eye on any throw is 0.739).
A random variable is normally distributed with mean 96.1 and a standard deviation of 7.9. what value is 2 standard deviations about the mean
A random variable is normally distributed with the mean 26.2 and a standard deviation 19.6. what value is 2 standard deviations below the mean?
2. If the given two sample data sets have the same standard deviation, are these samples necessarily identical? Justify your answer
The formula for the standard error (standard deviation of the distribution of sample means) implies that as the sample size (n) increases, the size of the standard error decreases. Explain the role... more
standard deviation question
What happens to the curve when the standard deviation is increased? What does that do to the area under the curve? What happens to the curve when the standard deviation is decreased? What does... more
The Census Bureau reports that 27% of California residents were born outside the Untied States. Suppose that you choose four Californians independent of each other and at random. Let F = the number... more
How to solve questions regarding drawing cards from a standard deck of 52?
Mark draws one card from a standard deck of 52. He receives $ 0.50 for a heart, $ 0.65 for a jack and $ 0.85 for the jack of hearts. How much should he pay for one draw?This is how i attempted to... more
How do i find the value thats one standard deviation below the mean ? I'm stuck on this part of my homework
Not sure how i'm suppose to solve this problem.The following data are the distances between a sample of 20 retail stores and a large distribution center. The distances are in miles.29; 30; 37; 40;... more
Data Management Probability, Standard Deviation, and Normal Distribution Question:
Hi, how would i get started on solving this question? The average monthly rainfall in Southern California is 26 mm. If rainfall data over the year is normally distributed with a standard deviation... more
Standard Deviation Mean
Mean of Test scores
the mean of normal distributed test score is 79 and the standard deviation is 5 if there are 242 test scores in the data sample how many of them were in the 84 to 94 range
STATS IN PSYCHOLOGY
Assume your class took a final exam in psychology in which the scores produced a normal curve with a mean score of 80 and a standard deviation of 5. If the student scores within two standard... more
Statistics with confidence intervals
A random sample of 80 college students was asked, “How many hours do you study each week?” After gathering the data, the sample has a mean of 14 hours and a standard deviation of 2.8 hours.... more
Intro to statistics
Suppose we want to estimate the average IQ score for the population of statistics students. What is the minimum number of statistics students that must be randomly selected for IQ tests if we want... more
probability in statistics
The number of hours an American adult sleeps each night follows a Normal distribution with an average of 6.9 hours per night with a standard deviation of 0.68 hours. If we randomly select one... more
Probability in statistics and standard deviation
The number of hours an American adult sleeps each night follows a Normal distribution with an average of 6.9 hours per night with a standard deviation of 0.68 hours. If we take a random sample of... more
Math Problem with Standard deviation and Expected Time
A survey was done on a group of people that asked the time, , it takes them to commute to work, rounded to the nearest 10 minutes. Use the probability distribution table below to answer Part 1-2.X... more