d. Identify the pair of independent variables that are the most strongly related to each other.

e. Identify the pair of independent variables that are the least strongly related to each other.

f. For the answer to part d, test to see if the population correlation coefficient (rho) for those two variables is different from zero. Use alpha = 0.05.

g. For the answer to part e, test to see if the population correlation coefficient (rho) for those two variables is different from zero. Use alpha = 0.05.

Excel sheet in link

https://docs.google.com/spreadsheets/d/1TL7blpx16llIqr_iLw_4D-V0n__f9dnvS57OZumxhXQ/edit?usp=sharing

In excell

• t-Test Assuming Equal Variances
• t-Test With Paired Two Samples for Means
• Analysis of Variance
• Correlation Coefficient
• Simple Regression

Skills and self-esteem are believed to influence job performance. To investigate this, an experimenter split 14 recent parolees into "high skill and self-esteem" and "low skill and self-esteem" groups. Three months later, employers were asked to rate each parolee’s job performance on a standard test that gives ratings from 1 to 10, with 10 being the highest. The following ratings were obtained for the individuals in the two groups:

a. Run descriptive statistics on the data. Please provide measures of central tendency and variability for the entire sample and also by groups.

b. Are there differences in job performance between the two groups? In your response, provide the answers to the following:

(i) The test you will run.

(ii) The null and research hypothesis.

(iii) The test results (copy the results to the word doc).

(iv) Your interpretation of the results.

Please do this task by R.

a) Revise the simulation shown in the lecture with the aim of constructing the empirical sampling distribution of beta_hat, based on 5000 trials.

b) According to the lecture, the mean of that histogram is supposed to be approximately equal to the true slope. Is it? Show code.

c) According to the lecture, the standard deviation of that histogram is supposed to be approximately equal to sigma_eps/sqrt(Sxx). Is it? Show code.

d) According to the lecture, the distribution of the beta_hat is supposed to be normal with certain parameters. Use qqnorm() and abline() to confirm that it is normal.

not sure if this help or not,

n = 10

n.trial = 64

x = c(1:n)

y_true = 10 + 2*x

sigma_eps = 15

par(mfrow=c(8,8),mar=c(0,0,0,0))

set.seed(123)

for(trial in 1:n.trial){

y_obs = y_true + rnorm(n,0,sigma_eps)

lm.1 = lm(y_obs ~ x)

plot(x, y_obs)

abline(10,2, col=2)

abline(lm.1, col=4)

}

Out of the variables provided below:

1) Select one dependent variable, one primary independent variable, and one potential confounding variable that will be used for linear regression.

2) State a possible research question and hypotheses (null and alternative) for these variables

Variables: Sex, Age, Education Level, Smoking Status, Employed, Minutes Exercised, Annual Income, Neighborhood

Using traditional methods, it takes 104 hours to receive a basic driving license. A new license training method using Computer Aided Instruction (CAI) has been proposed. A researcher used the technique with 100 students and observed that they had a mean of 105 hours. Assume the standard deviation is known to be 5. A level of significance of 0.05 will be used to determine if the technique performs differently than the traditional method. Is there sufficient evidence to support the claim that the technique performs differently than the traditional method?

The median US salary is $50,700, according to US Census data. Using a one-sample

t-test, test to see if participant income (INC1) is different from the national average. Use a two-tailed test and an alpha level of 5%.

1. Participant income is significantly greater than the national average
2. Participant income is significantly less than the national average
3. Participant income is not significantly different from the national average
4. Participant income cannot be compared to the national average

One-Sample Statistics

INCOME N=400 Mean=$47,112.92 Std. Deviation=$40,477.089 Std. Error Mean=$2,023.854

One-Sample Test

Test Value = 0

INCOME t=23.279 df=399 Sig. (2-tailed)=.000 Mean Difference=$47,112.920

95% Confidence Interval of the Difference

(lower)$43,134.17 (higher)$51,091.67

Beer drinkers order an average of 50 pitchers of beer per hour at Nick's Pub in

Bloomington, Indiana. Answer the following questions:

• What is the probability that at least 100 pitchers are ordered in a three-hour period?

• What is the chance that the time between ordered pitchers will be 45 seconds or less?

B.An average of 100 customers arrive each hour at the Central Forest Coffee Shop. What

is the probability that at least 170 customers arrive in a two-hour period?

An environmentalist wants to find out the fraction of oil tankers that have spills each month.

Step 2 of 2 :  

Suppose a sample of 516 tankers is drawn. Of these ships, 393 did not have spills. Using the data, construct the 90% confidence interval for the population proportion of oil tankers that have spills each month. Round your answers to three decimal places.

According to a recent article, 32% of drivers had driven drowsy in the past month. (Source: Thenationshealth.aphapublications.org/content/41/10/E52.fuII)

Suppose law enforcement officials are planning a survey of 1000 drivers to determine what proportion are driving drowsy.

a. Is whether a driver has driven drowsy in the past month qualitative or quantitative?

b. Would it be unusual if, in a random sample of 1000 drivers, 35% or more were driving drowsy in the last month? Include justifications for full credit.

c. What is the minimum number of drivers that must be sampled to be sure that the shape is approximately normal? Hint – use the formula

what applied statistical strengths exist in analyzing of TV and/or movie ratings?aa

A distribution of values is normal with a mean of 80 and a standard deviation of 18. From this distribution, you are drawing samples of size 13. Find the interval containing the middle-most 32% of sample means: Incorrect Enter your answer using interval notation. In this context, either inclusive or exclusive intervals would be acceptable. Your numbers should be accurate to 1 decimal places. Answers obtained using exact z-scores or z-scores rounded to 3 decimal places are accepted.

What’s the difference between parametric and non-parametric measures.

Describe the parameters for visual analysis of case study data. How does analysis through single case effect size statistics effect the confidence in our predictions?

Suppose that you as a researcher wanted to examine the impact of police officer rank on perceptions of friendliness by citizens in College Park, MD. Rank is measured as patrol officer, sergeant or captain, and citizen perception is captured by a scale ranging from -50 to 50 and measured in a survey given to 1,000 randomly selected people after an interaction with a police officer. 500 people talked to a patrol officer, 300 talked to a sergeant and 200 people talked to a captain.

3. What is the a) unit of observation and b) reasonable population for this sample?

4. Identify the a) independent and b) dependent variables.

5. For each variable, name what kind of variable it is (nominal, ordinal, interval, or ratio).