Although there is a popular belief that herbal remedies such as ginkgo biloba and ginseng may improve learning and memory in healthy adults, these effects are usually not supported by well-controlled research (persson, bringlov, nilsson, and nyberg, 2004). in a typical study, a researcher obtains a sample of n = 16 participants and has each person take the herbal supplements every day for 90 days. at the end of the 90 days, each person takes a standardized memory test. for the general population, scores from the test form a normal distribution with a mean of μ = 50 and a standard deviation of σ=12 . the sample of research participants had an average of m = 54 .

a. assuming a two-tailed test, state the null hypothesis in a sentence that includes the two variables being examined.
b. using the standard 4-step procedure, conduct a two-tailed hypothesis test with α = .05 to evaluate the effect of the supplements.

The swimming pool is open when the high temperature is higher than 20∘c. lainey tried to swim on monday and thursday (which was 33 days later). the pool was open on monday, but it was closed on thursday. the high temperature was 30 ∘c on monday, but decreased at a constant rate in the next 33 days. write an inequality to determine the rate of temperature decrease in degrees celsius per day, d, from monday to thursday.

1.3.25 question suppose 40​% of all voters voted for a particular candidate. to simulate exit polls regarding whether or not voters voted for this​ candidate, five random samples of size 1010 and five random samples of size 10001000 have been generated using technology using a population proportion of 0.400.40​, with the accompanying results. complete parts a through c below. click the icon to view the simulation results. a. observe how the sample proportions of successes vary around 0.400.40. simulation compared to sample prop simulation compared to sample prop 1 ▾ 6 ▾ greater than 0.40 less than 0.40 equal to 0.40 2 ▾ less than 0.40 greater than 0.40 equal to 0.40 7 ▾ greater than 0.40 less than 0.40 equal to 0.40 3 ▾ greater than 0.40 less than 0.40 equal to 0.40 8 ▾ equal to 0.40 greater than 0.40 less than 0.40 4 ▾ greater than 0.40 equal to 0.40 less than 0.40 9 ▾ less than 0.40 greater than 0.40 equal to 0.40 5 ▾ equal to 0.40 less than 0.40 greater than 0.40 10 ▾ equal to 0.40 greater than 0.40 less than 0.40 click to select your answer(s) and then click check answer. 2 parts remaining clear all check answer

The stem-and-leaf plot shows the heights in centimeters of teddy bear sunflowers grown in two different types of soil. soil a soil b 5 9 5 2 1 1 6 3 9 5 1 0 7 0 2 3 6 7 8 2 1 8 3 0 9 key: 9|6 means 69 key: 5|8 means 58 calculate the mean of each data set. calculate the mean absolute deviation (mad) of each data set. which set is more variable? how do you know?