Statistics 2.2

For ages of patients diagnosed with Alzheimer's disease​, state whether you would expect a histogram of the data to be​ bell-shaped, uniform, skewed​ left, or skewed right.

skewed left

The​ ______ class limit is the smallest value within the class and the​ ______ class limit is the largest value within the class.

lower, upper

The following frequency histogram represents the IQ scores of a random sample of​ seventh-grade students. IQs are measured to the nearest whole number. The frequency of each class is labeled above each rectangle. Use the histogram to answers parts​ (a) through​ (g). ​(a) How many students were​ sampled? (b) ​Determine the class width. ​(c) Identify the classes and their frequencies. Choose the correct answer below. ​(d) Which class has the highest​ frequency? (e) Which class has the lowest​ frequency? ​(f) What percent of students had an IQ of at least 130​? (g) Did any students have an IQ of 163​?

(a) 200 students (b) 10 (c) ​60-69, 1​; 70-79, 4; 80-89, 14​; ​90-99, 45​; 100-109, 48​; 110-119, 41​; ​120-129, 32; 130-139, 9​; 140-149, 4​; 150-159, 2 (d) 100-109 (e) 60-69 (f) 7.5 % (g) ​No, because there are no​ bars, or​ frequencies, greater than an IQ of 160.