STAT Homework assignment week 2 complete solutions correct answers key

STAT Homework assignment week 2 complete solutions correct answers key

(Total 9 problems)

7.          For the data from the 1977 Stat. and Biom. 200 class for eye color, construct:

             a.          pie graph

             b.          horizontal bar graph

             c.           vertical bar graph

             d.          a frequency table with the relative frequency of each eye color

Eye Color

Number of Students

Brown

11

Blue

10

Green

4

Gray

1

9.  Which of the box plots on the graph has a large positive skew?  Which has a large negative skew?

6.         You recorded the time in seconds it took for 8 participants to solve a puzzle.  These times appear below.  However, when the data was entered into the statistical program, the score that was supposed to be 22.1 was entered as 21.2.

You had calculated the following measures of central tendency:  the mean, the median, and the mean trimmed 25%.  Which of these measures of central tendency will change when you correct the recording error?

Time (seconds)

15.2

18.8

19.3

19.7

20.2

21.8

22.1

29.4

8.         You know the minimum, the maximum, and the 25^th, 50^th, and 75^th percentiles of a distribution.  Which of the following measures of central tendency or variability can you determine?  Mean, median, mode, trimean, geometric mean, range, interquartile range, variance, standard deviation

ADHD Treatment (AT) case study

30.       (AT) What is the mean number of correct responses of the participants after taking the placebo (0 mg/kg)?

31.       (AT) What are the standard deviation and the interquartile range of the d0 condition?

Use this case study for questions 30 and 31:

 Treatment Effects of a Drug on Cognitive Functioning in Children with Mental Retardation and ADHD



Research conducted by: Pearson et al. (2003, see reference below)

Case study prepared by: David Lane and Emily Zitek

Overview
 

This study investigated the cognitive effects of stimulant medication in children with mental retardation and Attention-Deficit/Hyperactivity Disorder. This case study shows the data for the Delay of Gratification (DOG) task. Children were given various dosages of a drug, methylphenidate (MPH) and then completed this task as part of a larger battery of tests. The order of doses was counterbalanced so that each dose appeared equally often in each position. For example, six children received the lowest dose first, six received it second, etc. The children were on each dose one week before testing.

This task, adapted from the preschool delay task of the Gordon Diagnostic System (Gordon, 1983), measures the ability to suppress or delay impulsive behavioral responses. Children were told that a star would appear on the computer screen if they waited “long enough” to press a response key. If a child responded sooner in less than four seconds after their previous response, they did not earn a star, and the 4-second counter restarted. The DOG differentiates children with and without ADHD of normal intelligence (e.g., Mayes et al., 2001), and is sensitive to MPH treatment in these children (Hall & Kataria, 1992).

Design Issues
This is a repeated-measures design because each participant performed the task after each dosage.

Descriptions of Variables
 

Variable

Description

d0

Number of correct responses after taking a placebo

d15

Number of correct responses after taking .15 mg/kg of the drug

d30

Number of correct responses after taking .30 mg/kg of the drug

d60

Number of correct responses after taking .60 mg/kg of the drug

References

Gordon M (1983), The Gordon Diagnostic System. DeWitt, NY: Gordon Systems

Hall CW, Kataria S (1992), Effects of two treatment techniques on delay and vigilance tasks with attention deficit hyperactive disorder (ADHD) children. J Psychol 126:17-25

Mayes SD, Calhoun SL, Crowell, EW (2002), The Gordon Diagnostic System and WISC-III Freedom from Distractibility index: Validity in identifying clinic-referred children with and without ADHD. Psychol Rep ,91, 575-587.

Pearson DA, Santos CW, Roache JD, Casat CD, Loveland KA, Lachar D, Lane DM, Faria, LF, Cleveland LA (2003), Treatment effects of methylphenidate on behavioral adjustment in children with mental retardation and ADHD. J Am Acad Child Adolesc Psychiatry, 42, 209-216.

Pearson, D.A., Santos, C.W., Jerger, S.W., Casat, C.D., Roache, J., Loveland, K.A., Lane, D.M., Lachar, D., Faria, L.P., & Getchell, C. (2003) Treatment effects of methylphenidate on cognitive functioning in children with mental retardation and ADHD. Journal of the American Academy of Child and Adolescent Psychiatry, 43, 677-685.

Links Methylphenidate

78.         Twenty-five randomly selected students were asked the number of movies they watched the previous week.  The results are as follows:

a.          Construct a histogram of the data

b.          Complete the columns of the chart.

Use the following information to answer the next two exercises:  Suppose one hundred eleven people who shopped in a special t-shirt store were asked the number of t-shirts they own costing more than $19 each.