Stats Help for College-level Students

Mean, median, mode, standard deviation and probability

Mean, median, mode, standard deviation and probability. Please look at the attachment.

Hypothesis testing

21st Century Insurance Company claims that telephone calls for policy holder information are answered in at most 3 minutes. A random survey of 36 phone calls results in the mean 3.3311 and standard deviation 2.1788. Is there sufficient evidence to disprove their claim? Alpha .05

Testing a claim given a confidence level, mean and standard deviation.

Sample data was collected in a study of calcium supplements and their effects on blood pressure. A placebo group and a calcium group began the study with blood pressure measurement. At a 0.05 significance level, test the claim that the 2 sample groups come from populations with the same mean. Placebo mean: 114.6538, standard d ...continues

Hypothesis testing: Chi square test for independence, confidence interval of standard deviation and variance

Problem 23: In one part of a test developed by a psychologist, the test subject is asked to form a word by unscrambling the letters "ciiatttsss". Given below are times (in seconds) required by 15 randomly selected persons to unscramble the letters. Construct a 95% confidence interval for standard deviation. Assume the population ...continues

Formula

A. (Ey)(Ex2)-(Ex)(Exy) / n(Ex2) - (Ex2) B. n(Exy) - (Ex)(Ey) / square root of n(Ex2) - (Ex)2 C. r= n(Exy) - (Ex)(Ey) / sq. root of [n(Ex2) - (Ex)2][n(Ey2) - (Ey)2

Descriptive methods: regression and correlation

A random sample of nine custom homes currently listed for sale provided the following information on size and price. Here , x denotes size, in hundreds of square feet, rounded to the nearest hundred, and y denotes price, in thousands of dollars, rounded to the nearest thousand. X 26 27 33 29 29 34 30 40 22 Y 259 274 294 29 ...continues

Descriptive methods in regression and correlation

Descriptive methods in regression and correlation

Find the following Z-statistics and associated probabilities. Does this provide enough evidence with a 95% confidence to infer that the population mean is less than 160? Determine if there is enough statistical evidence with 99% confidence to infer that the population mean is greater than 50. With a confidence level of 95%, test the hypothesis. Given the three states of correlation, explain how two data sets would move with each other in that state. Does this indicate that the population proportion of consumers loyal to Chevrolet is more than 47%.

The population data is normally distributed with a mean of 30 and a standard deviation of 5. Find the following Z-statistics and associated probabilities. 1. P(17 < X < 26) 2. P( X < 32) A population of yearly average rainfall for the Amazon jungle is normally distributed with a mean of 1000 inches and a standa ...continues

Binomial Probability Problem

If 90% of the U.S. citizens feel that the President is doing a satisfactory job,what is the probability that if 12 citizens are asked if the president is doing a satisfactory job that at least 9 will say yes?

Calculating a person's expectation at winning a lottery.

If 5,000 tickets are sold for $3 each and there will be one prize worth $5,000, a second prize worth $1,000 and a third prize worth $500, find one's expectation to win if they buy a ticket.