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Hypothesis Testing: Correlation

Related Topics

Wize University Statistics Textbook > Scatterplots, Association, and Correlation

Correlation

2 Activities

Wize University Statistics Textbook > Hypothesis Testing with One Sample

Introduction to Hypothesis Testing

2 Activities

Wize University Statistics Textbook > Continuous Probability Distributions

Normal Distribution

2 Activities

For the following statements, select true or false. Enter T for True, F for False.


More Correlation Questions:
The correlation between the number of hours of operation and sales in dollars at Pino's Pizza is 0.43. Which of the following is true?
Correlation and Regression Line
If r=−1.00r=-1.00, then 100% of the data points fall exactly on the regression line and the slope cannot be equal or greater than 0.
Correlation
The correlation between the number of hours of operation and sales in dollars at Pino's Pizza is 0.43. Which of the following is true?
Correlation
Numbers in a data set are in dollar units ($). Which of the following measures will not be in dollar units?
Correlation
Which of the following statements is/or TURE? (select all that apply)
Correlation
True or False: A correlation coefficient of 0.6 means that 60% of the data points in the scatter plot have a linear relationship.
Predictions and Residual Plots
Suppose the following summary data was given:
x-variable: μx=10, sx=2\mu_x=10,\ s_x=2
y-variable: μy=250, sy=10\mu_y=250,\ s_y=10
Correlation
If we double all the YY data and without changing the XX data, the correlation will not change but the slope will get steeper.
Correlation
If R2=0.86R^2=0.86, then there must be a strong, positive correlation between XX and YY.
Correlation
The correlation between the number of hours of operation and sales in dollars at Pino's Pizza is 0.43. Which of the following is true?
Correlation
If we swap xx and yy, what will happen to the correlation coefficient rr?
Correlation
The correlation between midterm grades and final exam grades is r=0.88r=0.88. The correlation between assignment grades and final exam grades is r=0.44r=0.44.
Which of the following is false?
Correlation
In a plot, if we swap xx and yy, rr will not change.
Correlation
r>0r>0; large values of xx are associated with large values of yy.
Correlation
r=−0.91r=-0.91; the correlation is very weak.
Correlation
r<0r<0; increasing xx will cause yy to decrease.
Correlation
r=−1.00r=-1.00; the correlation is perfectly negative.
Correlation
r=2.00r=2.00; the correlation is very strong.
Correlation
r=0.33r=0.33; the correlation is positive, but weak.
Correlation: Coefficient of Determination
True or false?
About 81% of the variation of quantities sold can be explained by price. The correlation between price and sales revenue is r=0.9r=0.9.
Simple Linear Regression: Correlation
True or false? Enter T if True, F if False. (Use capital letters: T, F)
1. If 𝒓 = −𝟏. 𝟎𝟎, then 100% of the data points fall exactly on the regression line and the slope cannot be equal or greater than 0.
T
Correlation
The correlation is 0.56 when the unit for xx is years. What will the correlation coefficient be after xx is changed from years to months of experience? [Enter your answer with 2 decimal places, e.g. 0.36]
Correlation
Correlation rr has no units unless xx and yy have the same units.
More Introduction to Hypothesis Testing Questions:
Hypothesis Testing
If the p-value is greater than the significance level we:
Hypothesis testing
When we reject the null hypothesis we are
Statistics: Definitions
One of the following statements is false. Which one is it?
Confidence Interval for a Mean
A t distribution is used instead of the normal z distribution when
More Normal Distribution Questions:
Normal Distribution
The weights of 10 week old puppies at a certain dog training school have a normal distribution with mean 12 lbs and a standard deviation of 4 lbs. The proportion of puppies that are heavier than 16 lbs is
Normal Distribution
IQ scores for 15 year olds are approximately normally distributed with mean 120 and standard deviation 16.
According to the 68-95-99.7% empirical rule, what proportion of 15 year olds have an IQ score between 88 and 152?
Normal Distribution
The weight of an apple from a certain apple tree is a random variable with mean 25g and variance 4g. What is the variance of the average weight of 25 randomly chosen apples?
Normal Distribution
The volume of juice boxes produced by a certain company follows the normal distribution with mean 125ml and standard deviation 2ml. Suppose the company will only ship out juice boxes with less 126ml. If the company wants to ship out 97.5% of juice boxes, by how much should the mean juice box volume be lowered in order for the company to achieve this shipping goal?
Normal Distribution
The weights of 10 week old puppies at a certain dog training school have a normal distribution with mean 12 lbs and a standard deviation of 4 lbs. The proportion of puppies that are heavier than 16 lbs is
Normal Distribution: Empirical Practice Problem
The number of calories consumed by an athlete varies according to a normal distribution with mean 2500 and standard deviation 100.
(a) What % of the days does this athlete consume under 2300 or between 2600 and 2700 calories?
(b) In a full year (365 days), approximately how many days do we expect him to consume between 2200 and 2300 calories?
Normal Distribution
Typically users of credit cards don’t pay on time.  The number of days a payment is made past the due date is normal with mean 2.5 days and standard deviation 0.30 days.
According to the empirical rule, what percent of users pay between 1.6 and 2.8 days late?
Normal Distribution
Typically users of credit cards don’t pay on time.  The number of days a payment is made past the due date is normal with mean 2.5 days and standard deviation 0.30 days.
According to the empirical rule, what percent of users pay more than 3.1 days late?
Normal Distribution
Frite Alors is a Montreal fast food chain specializing in burgers and poutine. If the amount of grams of cheese in a poutine follows a normal distribution:
50% of poutines have more than 230 grams of cheese, and 15.46% have less than 180 grams.
What is the mean of the amount of cheese?
Empirical Rule
Car batteries are designed to last on average 5 years with standard deviation of 1.3 years. Assume that battery life is normally distributed.
a) Using the 68-95-99.7% rule, what percentage of batteries will last between 2.4 and 3.7 years?
b) Using the 68-95-99.7% rule, what proportion of batteries will last under 2.4 years or more than 6.3 years?
Normal Distribution
About 95% of all transactions with a bank teller at HSBC take between 2 and 16 minutes, but the distribution is skewed to the right. We took a random sample of 101 customers at HSBC. Which of the following is true?
Normal Distribution
CLT (Cats Living Together) Agency has hundreds of cats up for adoption. The time it takes for a cat to get adopted is 25 days on average and is Normally distributed. If someone randomly samples 50 cats, which of the following is true?
Normal Distribution
Mean average employee salary at CLT (Cash Loving Tycoons) Corp is $89,450; but the median salary is $71,600. If someone randomly samples 7 employees, which of the following is true?
Normal distribution
95% of all Koka-Kola cans have between 150 ml and 200 ml of soda pop. According to the 68-95-99.7% rule, find the values of the mean and standard deviation of this distribution.
Normal distribution
A farmer needs to remove apples that weigh less than 80 grams. His trees grow apples that weight an average of 100 grams. About 3.75% of apples are too small. Assuming the weight of apples is normally distributed, what is the standard deviation of the weight of apples?
Normal distribution and standardizing
The random variable X has a normal distribution. If μ=20μ=20 and σ=4σ=4 find the value of aa such that P(16<X<a)=0.7357P(16<X<a)=0.7357. [Round aa to the nearest whole number.]
Normal Distribution and Standardizing
If X = 200, we get z = 2.00; and
if X = 115, we get z = –1.40
Solve for μ\mu and σ\sigma.
Standardizing: Normal Distribution
The exam grades in Hugh’s statistics class are normally distributed. If his z-score is 0.00, which of the following must be true?
Normal distribution: Standardizing
The average tips servers receive is normally distributed with a mean of 13.5% and a standard deviation of 4.5%. What is the probability of Trevor receiving more than 15% on a given bill?
Normal distribution
A random skills test was administered to a large group of students at a university. Suppose that the time the students took to complete the test is approximately normal with a mean of 40 minutes and a standard deviation of 10 minutes. If the top 20% of the students who completed the skills test the fastest get a prize, how fast must a candidate complete the test to get a prize?
Central Limit Theorem
Which of the following statements best describes the Central Limit Theorem?
Normal Distribution
Typically users of credit cards don’t pay on time.  The number of days a payment is made past the due date is normal with mean 2.5 days and standard deviation 0.30 days.
According to the empirical rule,
a) what percent of users pay more than 3.1 days late? (write % in 2 decimal places)
Normal Distribution: Standardizing
When calculating students' marks out of 25, their z-scores are also calculated. The average score was 17 and the standard deviation was 1.4. Test scores are normally distributed. Eric tells John "my teacher said I scored higher than 60% of the class". What's the lowest mark Eric could have had?