State whether each hypothesis is a null, directional or a non-directional hypothesis. Improved working conditions in a plant will lead to greater productivity. Students who do not cheat during examinations have higher self-esteem than students who cheat during examinations. A whole advertisement will lead to increased sales for the product. The proportion of detergent users who prefer Super Ola CClean is higher than 50% There is no difference between drug X and drug Y in relieving muscle pains.

The​ least-squares regression equation is y=620.6x+16,624 where y is the median income and x is the percentage of 25 years and older with at least a​ bachelor's degree in the region. The scatter diagram indicates a linear relation between the two variables with a correlation coefficient of 0.7004. In a particular​ region, 28.3 percent of adults 25 years and older have at least a​ bachelor's degree. The median income in this region is ​$37,389. Is this income higher than what you would​ expect? Why?

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A special education teacher did research on whether or not there is a relationship between the number of students in his class and the number incidents of “acting out” behaviors exhibited by the autistic students in the classroom. He collects data for a year and aggregates them by month. He obtained the statistics below,   r= -.863 R2=.74 b= -1.212294 a= 131.176598   10.) How does the presence of more students affect the incidents in the class? a) as students are added the incidences increase b) as students are added the incidences decrease c) the number of students does not affect acting out d) the number of students caused more incidents   How much of the variability of acting out is explained by the number of students in the class?___________

You run a regression analysis on a bivariate set of data ( n = 39). With regression equation a 24.8 and j = 43.4, you obtain the y = 2.058x with a correlation coefficient of r = 0.251. You want to 27.113 predict what value (on average) for the response variable will be obtained from a value of 180 as the explanatory variable. What is the predicted response value? y = (Report answer accurate to one decimal place.)

r. Lyte wishes to study speed of Reaction Time to press a button in response to the onset of a lamp.  The independent variable (IV) is the color of the light produced by the lamp (red, orange, yellow, green, or blue).  Since only 10 participants are available, she elects to administer the IV within-subjects with all 10 participants being exposed to all five levels of the color variable.  The order of the color of the light presentation is to be counterbalanced. Using concepts from the textbook, why would Dr. Lyte need to use counterbalancing in this scenario?

Identify the correct statement concerning, r the correlation coefficie between X and Y and the linear regression, Y = aX+b. A. Both can be used to show cause and effect. B. Both quantify the strength of relationship between X and Y. C. X and Y are interchangeable in both relationships. D. Both can be used to make predictions.

You take a survey that is supposed  to measure whether you are an extrovert or not. The score you get on the extrovert survey is a z-score of 2.0. What does that mean about your level of extraversion compared to the average score?

A certain training device measures reaction times of users by illuminating lights, one at a time, and measuring the time it takes the user to press each light to turn it off. The makers of the device are marketing it for high-level training, saying that even among professional athletes, the proportion who can score the top ranking of "light speed" is less than  22% . As a fitness trainer who wants to buy the device to attract more customers, you want to feel comfortable that the claim made by the makers is correct. To test the claim, you decide to perform a hypothesis test. To do so, you rent the device and have a random sample of  130  professional athletes use it;  26  score a ranking of "light speed."   You confirm that it is appropriate to perform a  Z -test. Why is a  Z -test appropriate?     Find  z , the value of the test statistic for your  Z -test. Round your answer to three or more decimal places. =z

To illustrate the effects of driving under the influence (DUI) of alcohol, a police officer brought a DUI simulator to a local high school. Student reaction time in an emergency was measured with unimpaired vision and also while wearing a pair of special goggles to simulate the effects of alcohol on vision. For a random sample of nine teenagers, the time (in seconds) required to bring the vehicle to a stop from a speed of 60 miles per hour was recorded. Complete parts (a) and (b). Note: A normal probability plot and boxplot of the data indicate that the differences are approximately normally distributed with no outliers. Click the icon to view the data table. (a) Whether the student had unimpaired vision or wore goggles first was randomly selected. Why is this a good idea in designing the experiment? A. This is a good idea in designing the experiment because it controls for any "learning" that may occur in using the simulator. B. This is a good idea in designing the experiment because…