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What is the relationship between the sign of the correlation coefficient and the sign of the slope of the regression line?
With a mean of 300 and a standard deviation of 80, how high a score do you need to be in the top 30%?
We have administered an anxiety test to all members of the class. The mean anxiety score is 71 and the standard deviation is 9. (higher score=higher anxiety)
A sample of households that subscribe to the United Bell Phone Company revealed the following numbers of calls received by each household last week. Determine the mean, median, and standard deviation
What statistical tests can perform to compare two groups asked the same question, when the question has a yes/no answer and the sample groups are different.
A sample of size n = 14 is selected from a normal population to construct a 95% confidence interval estimate for a population mean. The interval was computed to be (7.82 to 9.64). Determine the sample
Could you detail the value of using standard scores (Z scores) to compare relative performance of individual test scores.
If a person were to guess a number from 1-10, the chance of guessing a 4 would be 0.1. If 5 people were asked to guess a number from 1-10, the chance of guessing a 4 would be 0.5. The chance of 2 peop
In one region, the September energy consumption levels for single-family homes are found to be normally distributed with a mean of 1050 kWh and a standard deviation of 218 kWh. Find P45, which is the
A surgical technique is performed on eight patients. You are told that there is an 80% chance of success.
A newspaper finds that the mean number of typographical errors per page is five. Find the probability that:
The lengths of human pregnancies are normally distributed with a mean of 268 days and a standard deviation of 15 days. What is the probability that a pregnancy lasts at least 300 days?
A real estate agent has 2 tours. The first tour through N1and has 10 homes for sale, whereas the second tour through N2and has 5 homes for sale.
A recent article in a computer magazine suggested that the mean time to fully learn a new software program is 40 hours. A sample of 100 first-time users of a new statistics program revealed the mean t
Twenty students randomly assigned to an experimental group receive an instructional program; 30 in a second group do not. After 6 months, both groups are tested on their knowledge
You take a random sample of pizzas sold during a one hour period over the next week. Group 1 and Group 2 The results are shown in the table to the at the bottom of this. Does the ad campaign make a di
A manufacturer produces a batch of memory chips (RAM) and measures the mean-time-between-failures (MTBF). The manufacturer then changes a manufacturing process and produces another batch and again mea
Assume that the population of heights of male college students is approximately normally distributed with mean m of 68 inches and standard deviation s of 3.75 inches. A random sample of 16 heights is
Individual scores of a placement examination are normally distributed with a mean of 84.2 and a standard deviation of 12.8.
A coin was flipped 60 times and came up heads 38 times. (a) At the .10 level of significance, is the coin biased toward heads? Show your decision rule and calculations. (b) Calculate a p-value and int
Each student in an experiment was told to look at 100 cars and count the number of people wearing the seat belts. The mean score for the class was found to be 44, and standard deviation =7
Set up a model to test whether there are differences in mean ... DATA SET E Ages and Weights of 31 Randomly Chosen U.S. Nickels (n = 31 nickels) Nickels
A jar containing 100,000 marbles. There are 6 colors of marbles in the jar and they are present at frequencies of 2%, 2%, 4%, 10%, 57%, 25%.
Find a confidence interval for the mean assuming that each sample is from a normal population. Mean = 127, s = 27, n = 16. Find the 90% Confidence Interval.
Assume that the heights of 5 year old boys are normally distribued with a mean of 100cm and a standard deviation of 60. What is the sampling distribution of the mean for a sample size of 900 and its c