Show:
experimental design,graphs and measurements
probability
distributions
confidence levels and intervals
hypothesis
100
Consider the following scenario: In an attempt to obtain information of how the weights of students on campus (weights in terms of skinny, slender, appropriate, chunky, and obese) are distributed, a student sits in front of the library from 10-1pm everyday for a week and categorizes the wights of those who enter. After a week the student has recorded 825 weights. Identify the following: population, sample size, variable of interest, and variable level of measurement.
What is students on campus, 825 students, weight, and ordinal.
100
403 People were asked, "How often should smoke alarm batteries be changed?" Every year, Every few months, Every few years and Don't know. Of these 46.1% answered "Every year," 31% answered "Every few months" and 4.5% answered "Every few years." How many people answered "Don't know?" What are the odds someone answered "Every year"?
What is 74 people didn't know and the odds that someone answered "Every year" is 46.1 : 53.9.
100
For a certain normal population, it has been determined that u= 125 and sigma = 18. For samples randomly selected from this population, uxbar = 125 and sigmaxbar = 3.6. What was the sample size?
25
100
A survey of 80 recent fatal traffic accidents showed that 46 were alcohol related. What is the point estimate for the population proportion of fatal traffic accidents that are alcohol related? Write the symbol and value.
What is p-hat = .5750
100
Do women talk more than men? One study followed 200 men and 200 women, to answer the question. In this sample, women spoke an average of 16,215 words and men an average of 15,669 words. Sample standard deviation for women was 11,800 words and for men was 10,600 words. Hypothesis: pool yes or no Reject or Fail to Reject. conclusion:
Ho: u1 = u2, Ha: u1 > U2 yes pool Fail to reject null We cannot conclude that women speak more than men.
200
The following data gives the number of points scored during each basketball game last season. leaf unit 1.0 3 8 4 0 5 12445 6 00111468 7 68 What is the value of the 36th percentile?
What is 55
200
At a 20th high school reunion, all the classmates were asked the number of children they had. These are the results: #children: 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | p(children): .05 |.14 |.34|.24|.11|.07|.02|.02|.01| What is the average and standard deviation for the number of children of these graduates?
What is the average of 2.67 and the standard deviation of 1.5431
200
The time it takes a college student to fall asleep is a normally distributed variable with a mean of 20 minutes and a standard deviation of 6.3 minutes. If one college student is randomly selected what is the probability that he/she will take longer than 15 minutes to fall asleep? also find the zscore.
zscore = -.7937 p(x>15) = .7863
200
A random sample of size n is selected from a population with an unknown mean and a standard deviation of 43.5. Calculated a 95% confidence interval for u based on x-bar for each of the following cases. Assume the population is normally distributed. a) n = 20, x-bar = 10.31 b) n = 60, x-bar = 10.31 c) n = 200, x-bar = 10.31
a) (-8.754, 29.374) b) (-.6968, 21.317) c) (4.2813, 16.339)
200
37 out of a random sample of 100 adult americans who didn't attend college believe in extraterrestrials. 47 out of 100 adults who did go to college claimed they believed in extraterrestrials. Does this indicate that the proportion of people who believe in ET's and attended college is significantly larger than the proportion who believe in ET's and did not attend college. us a significance level of 10%.
Reject null 10% more college students believe in ET's than noncollege students.
300
The following information was gathered from a randomly selected sample of 600 american adults. Question was does love happen at first sight? 40% said it happens, 32% said no way, and 28% said it could happen. Complete a frequency distribution for this information. Category | Frequency | Relative Frequency.
Category | Frequency | Relative Frequency 1. It happens | 240 | .4 2. no way | 192 | .32 3. could happen | 168 | .28
300
Suppose you arrive at class and your teacher announces a pop quiz. There are ten multiple choice questions on this quiz, each with four responses. You were not expecting a quiz, so you must guess at each answer. What is the probability you will earn exactly 60% on the quiz?
What is .016.
300
Employees of a company are given a test that is distributed normally with mean 100 and variance 25. The top 5% will be awarded top positions with the company. What score is necessary for the top positions?
108.2245 or higher.
300
Case studies showed that out of 10,351 convicts who escaped from U.S. prisons, only 7867 were recaptured. Find the margin of error for a 90% confidence interval for the population proportion.
ME = .0069
300
To compare two elementary schools in teaching reading skills, 12 sets of twins were used. One child from a set of twins was sent to school A and the other twin was sent to school B. Below are their test scores. Test the hypothesis that both schools are equally as effective against the alternate hypothesis that the schools aren't equally effective. Twin pair | 1 | 2 | 3 | 4 | 5 | 6 | School A |177|150|112|95|120|117| School B |86 | 135|115|110|116|84 Twin Pair | 7 | 8 | 9 | 10 | 11 | 12 School A | 86|111|110|142|125|89 School B | 93| 77 | 96 |130|147|101
Fail to reject not enough evidence
400
The five number summary for statistics final exam scores is 36-67-75.5-86-98. a) what percentage of students scored 86 or higher? b) construct a box plot and describe the shape of the distribution. c) calculate the lower and upper fence.
What is 25%, long left whisker skewed left, 38.5 and 114.5
400
A woman has a particular trait that can be passed on to her children with 20% probability. Her husband has the same trait that he pass on with 35% probability. Suppose that the trait must be passed from both parents for the child to have it. Given the first child had the trait what is the conditional probability that the second child will also have the trait?
What is .0700.
400
CSUB alumni donations are known to be normally distributed with a mean of $75 and a standard deviation of $20. Beyond which dollar amount to we find 65% of the donations.
$67.29
400
An animal researcher wants to estimate the mean number of offspring per litter for tarantulas. She randomly samples 40 female tarantulas and observed a mean of 78.7 offspring and a standard deviation of 13.9 offspring. Construct a 99% confidence interval for the mean number of offspring for all tarantulas.
between 72.7 and 84.7
400
Is there any difference in the three population means uA. uB, and uC? Assume each sample was randomly and independently selected from a normal population. Sample A: 3 2 3 4 xbar = 3 Sample B: 5 6 5 5 xbar = 5.25 Sample C: 8 7 7 8 xbar = 7.5
Reject the Null there is enough evidence.
500
Consider a bell shaped symmetric distribution with a mean 22 and a standard deviation of 3.5. Draw a diagram of distribution. Use the Empirical Rule to estimate how much data you would expect to find between 15 and 22.
What is 47.5%
500
As a treatment for high blood pressure, twenty-eight stock brokers adopted either a cat or a dog, and the other 20 took and ACE inhibitor. Here are the results Pet | No Change | Lower Cat | 3 | 9 Dog | 4 | 12 None | 15 | 5 Is being a pet owner independent of blood pressure status?
no, they are dependent.
500
Only 30% of all single parents own their homes. Consider a random sample of size n = 100 from this population (they either own their home or they do not) with pi = 0.3 what is the largest p-hat you might see from this sample?
What is .4374
500
Below are the calories of the 10 pieces of candy you just ate. 80 95 76 100 90 85 100 82 90 110 Find a 98% confidence interval.
use median 2nd and 8th positions which were 80 and 100
500
A survey of 250 people was conducted recently to see if there is a relationship between a person's education level and political party affiliation. Does the data below suggest that educational level and political affiliation are dependent?
At a 5% significance level there is not enough evidence to suggest that educational level and party affiliation are dependent.