StudentD
Most popular questions and responses by StudentD
Statistiscs
Students in the psychology department consume an average of 5 cups of coffee per day with a standard deviation of 1.75 cups. The number of cups of coffee consumed is normally distributed. • What proportion of students consume an amount equal to or less
asked on August 28, 2012 
statistics/ Help!thanks!
The producers of a new toothpaste claim that it prevents more cavities than other brands of toothpaste. A random sample of 60 people use the new toothpaste for 6 months. The mean number of cavities at their next check up is 1.5. In the general population
asked on August 25, 2012 
statistics
In a psychology class of 100 students, test scores are normally distributed with a mean of 80 and a standard deviation of 5. Approximately what percentage of students have scores between 70 and 90? A. 68% B. 80% C. 95% D. 99%
asked on August 15, 2012 
Statistics
If weight in the general population is normally distributed with an average of 160 and a standard deviation of 20 pounds, what is the probability of selecting someone who weights 120 or less or 170 or more pounds?
asked on August 28, 2012 
Statistics
For a hypothetical normal distribution of test scores, approximately 95% fall between 38 and 62, 2.5% are below 38, and 2.5% are above 62. Given this information, (a) the mode=_____ and (b) the standard deviation=_____ Thanks in advance!
asked on August 28, 2012 
statistics
Faculty in the psychology department at APUS consume an average of 5 cups of coffee per day with a standard deviation of 1.5. The distribution is normal. How many cups of coffee would an individual at the 25th percentile drink per day? A. 4 B. 5 C. 6 D. 7
asked on August 15, 2012 
Statistics
If weight in the general population is normally distributed with an average of 160 and a standard deviation of 20 pounds, what is the probability of selecting someone who weights 120 or less or 170 or more pounds?
asked on August 28, 2012 
Statistics
Calculate the Pearson productmoment correlation for the data below. X 3 4 2 1 Y 5 5 3 4
asked on August 28, 2012 
statistics/ Help!
What is the probability of pulling a heart from a standard (52card) deck of playing cards? A. .25 B. .50 C. .75 D. 1.0 Thanks very much!
asked on August 21, 2012

Statistiscs
z = (6  5)/1.75 = 0.57 .2157+.50= 0.7157x100=71.57% i.e 71.57% In the second part, find z using a ztable for the 80th percentile. Plug into the formula, along with mean and standard deviation. Solve for x. z = (x  mean)/sd z (sd)= Xmean z (sd)+mean= X
posted on August 29, 2012 
Statistics
Thanks. For the z scores I have: z = (120  160)/20 = 40/20=2 z = (170  160)/20 = 10/20= 0.5 and the z table for 2 (area between Mean and z) 0.47725, area beyond: 0.02275 For 0.5: 0.19146 and area beyond: 0.30854 What do I do after that, and which # I
posted on August 29, 2012 
Statistics
Thank you very much! I am having real problems with that. Is that the formula that should be used: ơ=√∑ (x µ)2/N ?
posted on August 29, 2012