The Weschler Intelligence Scale for Children (WISC) is an intelligence test designed for children between the ages of 6 and 16.
The test is standardized so that the mean score for all children is 100 and the standard deviation is 15.
Suppose that a very large and competitive school district, administrators wish to estimate the mean WISC score for all students enrolled in their programs for gifted and talented children. They obtained a random sample of 40 students currently enrolled in at least one program for gifted and talented children. The test scores for this sample are as follows:
126,111,141,96,123,115,116,113,127,114,122,116,104,126,126,132,139,111,143,121,
119,107,154,125,120,135,142,132,94,103,143,115,132,107,118,105,101,135,94,153
Use this data to calculate the mean WISC score, x⎯⎯, for these 40 students. Next, compute the standard error of the mean, SE, assuming that the standard deviation of WISC scores for students in the district is the same as for the population as a whole. Finally, determine both the lower and upper bounds of a 90% confidence interval for μ, the mean score for all students in the school district who are enrolled in gifted and talented programs.
Give x⎯⎯ (line is supposed to be on top of x) and the bounds of the confidence interval precise to one decimal place, but give the standard error to at least two decimal places in order avoid rounding errors in the bounds of the confidence interval.
x⎯⎯ (line is supposed to be on top of x)=_______
SE=_______
Lower bound=_______
Upper bound=_______
