The Iowa Tests of Educational Development Are Given Each Year

question 8

Essay

The Iowa Tests of Educational Development are given each year to students around the country. Let x = the previous year's science scores and y = the current year's science scores for a sample of current sophomores who took the test both years.
b = estimated slope of the regression line = 0.93
a = estimated y intercept of the regression line = 30.36
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a)What is the equation of the estimated regression line?
b)On the graph below, sketch the estimated regression line using the information above. Be sure to label and scale your axes correctly.
c)For students with a score of 250 the previous year, what is the predicted score for the current year?
d)What is the average difference in science score that is associated with a 10-point difference in the previous year's science score?
e)The value of r² is 0.71; interpret r² in the context of this problem.
f)The value of s_e is 25.5. Interpret s_e in the context of this problem.

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Definitions:

Pericycle

A layer of meristematic cells typically found between the endodermis and phloem in roots.

Parenchyma Cells

A type of plant cell known for its role in photosynthesis, storage, and tissue repair and regeneration.

Horizontal Pathway

A gene transfer method in which genetic information moves between organisms in a manner other than traditional reproduction.

Soil

The top layer of earth in which plants grow, composed of organic matter, minerals, gases, liquids, and organisms that together support life.