A neurologist wishes to determine if age affects how quickly a person reacts in a stressful situation, such as being asked on the spot to talk about themselves for a minute Data on the ages and reaction times of a group of randomly chosen people are collected and shown below. Age (years) Reaction Time (seconds) 10 8 12 7.5 12 8 15 19 6.5 22 6 25 26 4 29 4.5 32 3.5 32 35 3 38 2.8 a Create a scatter plot and determine the line of best fit. b. Determine the equation of the line of best fit and comment on the strength of the correlation c Predict the reaction time of a 30 year old

Data was collected for a sample of organic snacks. The amount of sugar (in mg) in each snack is summarized in the histogram below. Frequency 10 8 6 4 2 100 101 102 103 104 105 106 10 amount of sugar (mg) What is the frequency of 102 mg of sugar? snacks

Researchers studying pleasant touch sensations measured the firing frequency (impulses per second) of nerves that were stimulated by a light brushing stroke on the forearm and also recorded the subject's numerical rating of how pleasant the sensation was. The accompanying data was read from a graph in a paper. Firing Frequency 23 24 22 25 28 27 34 32 37 34 Pleasantness Rating 0.1 1.0 1.2 1.2 1.0 2.0 2.3 2.2 2.5 2.7 (a) Estimate the mean change in pleasantness rating associated with an increase of 1 impulse per second in firing frequency using a 95% confidence interval. (Use technology to find the critical value. Round your answers to three decimal places.) Interpret the resulting interval. O We are 95% confident that the mean change in firing frequency associated with an increase of 1 in pleasantness rating is in this interval. We are 95% confident that the mean change in firing frequency associated with an increase of 1 in pleasantness rating is outside this interval. We are 95%…

A federal regulatory agency is investigating an advertised claim that a certain device can increase the gasoline mileage of cars (mpg). Ten such devices are purchased and installed in cars belonging to the agency. Gasoline mileage for each of the cars is recorded both before and after installation. The data are recorded here.   Car         1 2 3 4 5 6 7 8 9 10 n x s Before (mpg) 19.1 29.9 17.6 20.2 23.5 26.8 21.7 25.7 19.5 28.2 10 23.22 4.25 After (mpg) 25.8 23.7 28.7 25.4 32.8 19.2 29.6 22.3 25.7 20.1 10 25.33 4.25 Change (mpg) 6.7 −6.2 11.1 5.2 9.3 −7.6 7.9 −3.4 6.2 −8.1 10 2.11 7.54 (a) The cars in the study appear to have grossly different mileages before the devices were installed. Use the change data to test whether there has been a significant gain in mileage after the devices were installed. Use ? = .05. H0: ?after         ?before Ha: ?after         ?before t =   p-value