Probability and Statistics
posted by Kim .
A research psychologist believes that professional athletes tend to be more confident than the typical person. From previous testing, he knows that the scores for people in the general population are approximately normally distributed with a mean of 72 and standard deviation of 14. A random sample of 15 athletes produces a sample mean of 76.5 with a sample standard deviation of 12.5. Is there enough evidence at he alpha= 0.10 significance level to indicate that professional athletes are more confident?

Probability and Statistics 
PsyDAG
Z = (mean1  mean2)/standard error (SE) of difference between means
SEdiff = √(SEmean1^2 + SEmean2^2)
SEm = SD/√n
If only one SD is provided, you can use just that to determine SEdiff.
Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion related to the Z score.
Respond to this Question
Similar Questions

statistics
The Intelligence Quotient (IQ) test scores are normally distributed with a mean of 100 and a standard deviation of 15. What is the probability that a person would score 130 or more on the test? 
statistics
Sat scores l around the nation tend to have a mean score around 500, a standard deviation of about 100 points and are approximately normal distributions. a person who scores 600 on the sat 1 has approximately what percentile rank within … 
Statistics
SAT I scores around the nation tend to have a mean scale score around 500, a standard deviation of about 100 points, and are approximately normally distributed. What SAT I score within the population would have a percentile rank of … 
statistics
SAT I scores around the nation tend to have a mean scale score around 500, a standard deviation of about 100 points, and are approximately normally distributed. What SAT I score within the population would have a percentile rank of … 
statistics
Just wondering if someone is able to give instructions as to how to go about this questions? 
statistics college
SATI SCORES AROUND THE NATION HAVE A MEAN SCORE AROUND 500 A STANDARD DEVIATION OF ABOUT 100 POINTS AND ARE APPROXIMATELY NORMALLY DISTRIBUTED A PERSON WHO SCORES A PERFECT SCORE OF 800 ON THE SAT I HAS APPROXIMATELY WHAT PERCENTILE … 
statistics
SAT I scores around the nation tend to have a mean scale score around 500, a standard deviation of about 100 points, and are approximately normally distributed. What SAT I score within the population would have a percentile rank of … 
Statistics
The next three questions refer to the following situation. Data from previous years reveal that the distribution if first exam scores in an introductory statistics class is approximately normal with a mean of 72 and a standard deviation … 
Math (Statistics)
The SAT scores of a certain population of students are approximately normally distributed with a mean and standard deviation of 1000 and 200 points, respectively. The probability that a student selected at random from the population … 
statistics
Membership in Mensa requires an IQ score above 131.5. Nine candidates take an IQ test and their summary scores indicate that their mean IQ score is 133. IQ scores are normally distributed and have a mean of 100 and a standard deviation …