Math 119 Three Situations exam part 2
name:_______________________
Blissymbols are pictographs sometimes used to help learning-disabled children. In a
study of computer-assisted learning, 12 normal-ability schoolchildren were assigned at
random to each of four computer learning programs. After they used the program, they
attempted to recognize 24 Blissymbols. Here are the counts correct for one of the
programs:
12 22 9 14 20 15 9 10 11 11 15 10 6
1. Give a 90% confidence interval for the mean count of correct among all children of
this age who use the program.
2. If the mean test score among schoolchildren who have not used this computer-assisted
learning program is 11.5, is there significant evidence that this program improves
Blissymbol recognition? (Justify your answer. Be sure to state your hypotheses and
significance level.)
A sample survey funded by the National Science Foundation asked a random sample of
1484 American adults about biological evolution. One question asked subjects to answer
“True”, “False”, or “Not sure” to the statement “Human beings, as we know them today,
developed from earlier species of animals.” Of the 1484 respondents, 594 said “True.”
3. What can you say with 95% confidence about the percent of all Americans adults who
are aware that humans developed from earlier species of animals?
4. The equivalent question for Northern Europeans yielded 75% to 82% “True” answers.
European academics have often suggested that this is a cultural-political debate mostly
limited to the United States. Does this survey reveal statistically significant evidence that
this is more of an American issue than a Northern Europe issue? (Justify your answer.
Be sure to state your hypotheses and significance level.)