Aresearcher performed an experiment with two groups. she found the difference of the means for each group. then she combined the groups, chose two new groups, and found the difference between the means of those new groups. she repeated this process 200 times. the normal distribution of the difference in the means she found is given below. how great would the difference in means between the first two groups have to be in order to considered significant?

a) at least 7
b) at least 8
c) at least 9
d) at least 10

could someone explain it to me?

(05.02) mr. morris is going to save money and replace his sailboat's mainsail himself. he must determine the area of the mainsail in order to buy the correct amount of material. calculate the area of the parallelogram to determine how much material should be purchased. be sure to explain how to decompose this shape into rectangles and triangles. describe their dimensions and show your work.

1. why is a frequency distribution useful? it allows researchers to see the "shape" of the data. it tells researchers how often the mean occurs in a set of data. it can visually identify the mean. it ignores outliers. 2. the is defined by its mean and standard deviation alone. normal distribution frequency distribution median distribution marginal distribution 3. approximately % of the data in a given sample falls within three standard deviations of the mean if it is normally distributed. 95 68 34 99 4. a data set is said to be if the mean of the data is greater than the median of the data. normally distributed frequency distributed right-skewed left-skewed

Sally deposited money into a savings account paying 4% simple interest per year. the first year, she earned $75 in interest. how much interest will she earn during the following year? show your work and explain your reasoning in the space provided below.