A nutrition store in the mall is selling "memory booster" which is a concoction of herbs and minerals that is intended to improve memory performance. To test the effectiveness of the herbal mix, a researcher obtains a sample of n=16 participants and has each person take the suggested dosage each day for 4 weeks. At the end of the four week period, each individual takes a standard memory test. The scores from the participants produced a M=26 with a sample variance of s2=64. In the general population, the standardized test is known to have a μμ=20.
a. Do the sample data support the conclusion that memory booster has a significant effect? Use a two-tailed test with αα=.05.
b. Compute Cohen's d to measure the size of the treatment effect.
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- The Cadet is a popular model of sport utility vehicle, known for its relatively high resale value. The bivariate data given below were taken from a sample of Cadets, each bought new two years ago, and each sold used within the past month. For each Cadet in the sample, we have listed both the mileage x (in thousands of miles) that the Cadet had on its odometer at the time it was sold used and the price y (in thousands of dollars) at which the Cadet was sold used. With the aim of predicting the used selling price from the number of miles driven, we might examine the least-squares regression line, =y−41.990.51x . This line is shown in the scatter plot below. Based on the sample data and the regression line, complete the following. (a)For these data, mileages that are less than the mean of the mileages tend to be paired with used selling prices that are ▼(Choose one) the mean of the used selling prices. (b)According to the regression equation, for an increase of…arrow_forwardAbove Answer is Wrong, Please Help!arrow_forwardThe Cadet is a popular model of sport utility vehicle, known for its relatively high resale value. The bivariate data given below were taken from a sample of fifteen Cadets, each bought new two years ago, and each sold used within the past month. For each Cadet in the sample, we have listed both the mileage x (in thousands of miles) that the Cadet had on its odometer at the time it was sold used and the price y (in thousands of dollars) at which the Cadet was sold used. The least-squares regression line for these data has equation y = 40.63 - 0.46x . This line is shown in the scatter plot below. Mileage, x(in thousands) Used selling price, y(in thousands of dollars) 23.9 29.5 37.6 22.6 20.8 30.9 23.3 33.1 28.3 26.1 27.3 29.9 27.7 29.8 20.9 30.3 25.8 27.2 34.4 25.9 23.9 27.4 23.8 27.5 23.2 31.4 15.6 34.0 29.4 27.7 Send…arrow_forward
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