Research has shown that IQ scores have been increasing for years (Flynn, 1984, 1999). The phenomenon is called the Flynn effect and the data indicate that the increase appears to average about 7 points per decade. To examine this effect, a researcher obtains an IQ test with instructions for scoring from 10 years ago and plans to administer the test to a sample of n = 25 of today’s high school students. Ten years ago, the scores on this IQ test produced a standardized distribution with a mean of m = 100 and a standard deviation s = 15. If there actually has been a 7-point increase in the average IQ during the past ten years, then find the power of the hypothesis test for each of the following. a. The researcher uses a two-tailed hypothesis test with a = .05 to determine whether the data indicate a significant change in IQ over the past 10 years. b. The researcher uses a two-tailed hypothesis test with a = .01 to determine whether the data indicate a significant increase in IQ over the past 10 years
Continuous Probability Distributions
Probability distributions are of two types, which are continuous probability distributions and discrete probability distributions. A continuous probability distribution contains an infinite number of values. For example, if time is infinite: you could count from 0 to a trillion seconds, billion seconds, so on indefinitely. A discrete probability distribution consists of only a countable set of possible values.
Normal Distribution
Suppose we had to design a bathroom weighing scale, how would we decide what should be the range of the weighing machine? Would we take the highest recorded human weight in history and use that as the upper limit for our weighing scale? This may not be a great idea as the sensitivity of the scale would get reduced if the range is too large. At the same time, if we keep the upper limit too low, it may not be usable for a large percentage of the population!
Research has shown that IQ scores have been increasing for years (Flynn, 1984, 1999). The phenomenon is called the Flynn effect and the data indicate that the increase appears to average about 7 points per decade. To examine this effect, a researcher obtains an IQ test with instructions for scoring from 10 years ago and plans to administer the test to a sample of n = 25 of today’s high school students. Ten years ago, the scores on this IQ test produced a standardized distribution with a
Trending now
This is a popular solution!
Step by step
Solved in 2 steps
