The Ice Chalet offers dozens of different beginning ice-skating classes. All of the class names are put into a bucket. The 5 P.M., Monday night, ages 8 to 12, beginning ice-skating class was picked. In that class were 64 girls and 16 boys. Suppose that we are interested in the true proportion of girls, ages 8 to 12, in all beginning ice-skating classes at the Ice Chalet. Assume that the children in the selected class are a random sample of the population.

a.) Calculate the following:
x = _______

b.) Calculate the following:
n = _______

c.) Calculate the following:
p′ = _______

d.) If we construct a 92% Confidence Interval for the true proportion of girls in the ages 8
to 12 beginning ice-skating classes at the Ice Chalet, how much area is in each tail?

The Genetics and IVF Institute conducted a clinical trial of the YSORT method designed to increase the probability that a baby is a boy. Among the babies born to parents in this trial, 172 were boys and 39 were girls. Use the sample data with a 0.01 significance level to test the claim that with the YSORT method, the probability of a baby being a boy is greater than 0.5.

What are some implications of differences in the ways adults speak to boys and girls?

What can parents and caregivers do to promote infants’ language development?

How does learning language during this age help develop cognitive skills in the future?

Do you tend to agree with Bruner or Piaget concerning the relationship between language and thought?

Which of the following statements is NOT true when describing a proportionate mortality rate?

A) When calculating this measure, all deaths for the period of study are included in the denominator.

B) This measure is expressed as a percentage of all deaths.

C) This measure is used to describe the proportion of deaths in a defined population that is attributable to a specific cause.

D) This measure is used to describe the total number of deaths in a defined population, including all causes.

Tourette Syndrome is the involuntary twitching of motor or vocal muscles. It usually presents symptoms in adolescence and is much more common among boys than girls. You are researching Tourette syndrome for the CDC and find the following information. Your study population is 87,026

Number of People in Study Number of People Diagnosed:

Boys 46,410 191

Girls 40,616 154

Age 6-11 37,775 169

Age 12-17 49,251 176

What is the prevalence of Tourette Syndrome in your study?

A) 1.77/1000

B) 3.96/1000

C) 3.79/1000

D) 7.93/1000

1. A science teacher claims that the mean scores on a science assessment test for fourth grade boys and girls are equal. The mean score for 63 randomly selected boys is 151 with a standard deviation of 36, and the mean score for 65 randomly selected girls is 149 with a standard deviation of 34. At α = 0.10, can you reject the teacher’s claim? Assume the populations are normally distributed and the population variances are equal.
   Resource: Two Samples, Means, sigma known
2. In a random sample of 1216 U.S. adults, 966 favor using mandatory testing to assess how well schools are educating students. In another random sample of 1202 U.S. adults taken 9 years ago, 893 favored using mandatory testing to assess how well schools are educating students. At α = 0.05, can you support the claim that the proportion of U.S. adults who favor mandatory testing to assess how well schools are educating students is more than it was 9 years ago?

   Resource: Two Samples, Proportions

1) Industry Research polled teenagers on sunscreen use. The survey revealed that 46% of teenage girls and 30% of teenage boys regularly use sunscreen before going out in the sun.  

identify the two populations
A. teenage girls and teenage boys who use sunscreen regularly
B. all teenagers
C. teenage girls and teenage boys
D. None of the above


identify the specified attribute
A. being a teenage girl or a teenage boy
B. being a teenager
C. uses sunscreen before going out in the sun
D. None of the above


are the proportions 0.46 (46%) and 0.30 (30%) population proportions or a sample proportions?
A. population proportions
B. sample proportions
C. None of the above

2) Select True or False from each pull-down menu, depending on whether the corresponding statement is true or false.

  ?    True    False      1. The number of degrees of freedom associated with the ?t test, when the data are gathered from a matched pairs experiment with 10 pairs, is 9.

  ?    True    False      2. The best estimator of the difference between two population means ?1−?2 is the difference between two sample means ?¯1−?¯2x

  ?    True    False      3. In testing the difference between two population means using two independent samples, the sampling distribution of the sample mean difference ?¯1−?¯2x is normal if the sample sizes are both greater than 30.

  ?    True    False      4. A political analyst in Iowa surveys a random sample of registered Democrats and compares the results with those obtained from a random sample of registered Republicans. This is an example of two independent samples.

Below is the the number of hours of TV watched by boys and girls per week. Using the data on the number of hours of TV viewing, test the hypothesis that the number of hours of TV watched by girls is less than 7.4 hours per week at a 2% significance level.

State the null hypothesis, H₀ and the alternative hypothesis, H₁

Below is the the number of hours of TV watched by boys and girls per week. Using the data on the number of hours of TV viewing, test the hypothesis that the number of hours of TV watched by girls is less than 7.4 hours per week at a 2% significance level.

Determine the critical values that divide the rejection and nonrejection regions

1) If the boys and girls have the same probabilities of being born. What is the probability that a family of 5 children selected randomly has atleast one boy?

2) Of the pieces produced by a machine in particular, 0.8% are defective. If an aleatory sample of 8 pieces produced by this machine contains two or more defective pieces, the machine will be turned off to make reparations. Find the probability that the machine would turn off for reparations based on the sampling plan.

As the director of the local Boys and Girls Club, you have claimed for years that membership in your club reduces juvenile delinquency. Now, a cynical member of your funding agency has demanded proof of your claim. Random samples of members and nonmembers are gathered and interviewed with respect to their involvement in delinquent activities. Each respondent is asked to enumerate the number of delinquent acts he/she has engaged in over the past year. The average number of admitted acts of delinquency are reported below. What can you tell the funding agency? Use an alpha of .01.

First, identify your (a) independent and (b) dependent variables.

Second, identify the (c) level of measurement for your independent variable and (d) the level of measurement for your dependent variable.

Third, (e) list out the steps of the 6 step traditional hypothesis test.

Fourth, (f) run a 6 step traditional hypothesis test.

(Conduct a 6 step traditional hypothesis test, find the p value).