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Normal Distrubutions
Scatterplots/Correlation
Confidence Intervals
Probability
Testing a Claim/Significance
100
__% of the observations fall within 2 standard deviations of the mean (mu).
What is 95% of observations.
100
State the response and explanatory variables. -Car weight - accident death rate
What is Response variable- Accident death rate Explanatory variable- Car weight
100
When does the margin of error of a confidence interval get smaller? I. the confidence level C decreases II. the confidence level C increases III. the sample size n increases a) I only b) II & III c) III only d)I & III e) none
What is d) I & III I. the confidence level C decreases III. the sample size n increases
100
If two events (A and B) have no outcomes in common and can never occur together, if P( A and B) = 0, they are known as.
What is mutually exclusive (disjoint).
100
What is the term for the probability (assuming Ho is true), that the statistic will take a value at least as extreme as the observed result in the direction specified by Ha.
What is the p-value of the test
200
What is the formula for a standardized score with known mean and standard deviation?
What is z-score (z) = x- mean ---------------- std. deviation
200
The graph displaying the relationship between 2 quantitative variables measured on the same individuals.
What is a scatterplot
200
Our 95% Confidence Interval for Ana's mystery mean was (230.80,250.80). How do we interpret this interval?
What is We are 95% confident that the interval from 230.80 to 250.80 captures the true mystery mean chosen by Ana.
200
If P(A|B) = P(A) & P(B|A) = P(B), they are known as
What is independent events
200
If the p-value is lower than the significance level, we a) fail to reject the null hypothesis b) reject the null hypothesis
What is b) reject the null hypothesis
300
The density curve: a) is always on the vertical axis b) exactly describes a set of data c) has an exact area of 1 underneath it
What is c) has an exact area of 1 underneath it
300
What letter is used to represent the correlation? a) t b) q c) c d) r e) p
What is d) r. Correlation 'r'
300
What are the conditions for constructing a confidence interval about a population proportion?
What is Checking Randomness, <10% Condition, Large Counts condition.
300
What is the general addition rule formula? P (A or B)
What is P (A or B)= P(A U B)= P(A)+ P(B) -P(A∩B)
300
If we fail to reject the null hypothesis when the alternative is true, we are committing what type of error.
What is a Type II error.
400
Alex's score on Exam 1 in his stats class was at the 64th percentile of the scores for all students. His score falls between: a) between the minimum and first quartile. b) between the first quartile and the median c) between the median and the third quartile d) at the mean score of all students.
What is c) between the median and the third quartile
400
The fraction of the variation in the values of y that is explained by the least- squares regression of y on x is a) the correlation b) the slope of the LSRL c) the square of the correlation coefficient d) the intercept of the LSRL e) the residual.
What is c) the square of the correlation coefficient
400
A inspector will measure the salt content(mg) in a random sample of bags of chips from an hour of production. Which would result in the smallest margin of error in estimating the mean salt content (mu)? a) 90% confidence; n=25 b) 90% confidence; n=50 c) 95% confidence; n= 25 d) 95% confidence; n=50 e) n=100 at any confidence level
What is b) 90% confidence; n=50
400
An athlete suspected of using steroids is given 2 tests that operate independently of each other. Test A has a probability .9 of being positive if steroids have been used. Test B has probability .8 of being positive if steroids have been used. What is the probability that neither test is positive if steroids have been used? a) .72 b) .38 c) .02 d) .28 e).08
What is c) .02.
400
The z- statistic for a test of Ho: p=.4 Ha: p≠.4 is z=2.43. This test is a) not significant at either α=.05 or α=.01 b) significant at α=.05 but not at α=.01 c) significant at α=.01 but not at α=.05 d) significant at both α=.05 and α=.01 e) inconclusive: p̂ value is not known
What is b) significant at α=.05 but not at α=.01
500
The average yearly snowfall in Kiko has a mean of 55 inches. If the snowfall exceeds 60 inches in 15% of the years, what is the standard deviation?
What is 4.83 inches.
500
Which is not a characteristic of the LSRL? a) the slope is always between -1 and 1 b) it always goes through the point (x̄,y-) (x-bar, y-bar) c) it minimizes the sum of squared residuals d) The slope will always have the same sign as correlation e) it is not resistant to outliers
What is a) the slope is always between -1 and 1
500
What is the formula for calculating a confidence interval for a population mean?
What is an is x¯± t ∗ s --- √n
500
Suppose a loaded die has the following probability model: Outcome: 1 | 2 | 3 | 4 | 5 | 6 | Probability:0.3|0.1|0.1|0.1| 0.1| 0.3| If this die is thrown & the top face shows an odd number, what is the probability the die shows a 1? a) .10 b) .17 c).30 d) .50 e) .60
What is e) .60
500
In a test of Ho: p=.4 Ha: p≠.4, a random sample size of 100 yields a test statistic of z=1.28. The p-value of the test is approximately equal to: a)0.90 b) 0.40 c) 0.05 d) 0.20 e) 0.10
What is d) 0.20.