Question

VANUIT IJS d lauluduLIVE TUI Of the element Darum that decays very rapidly. It is easy and safe to use for lab experiments in schools and colleges. In a typical experiment, the radioactivity of a sample of barium-137m is measured for one minute. It is then measured for three additional one-minute periods, separated by two minutes. So data are recorded at 1, 3, 5, and 7 minutes after the start of the first counting period. The measurement units are counts. Here are the data for one of these experiments. Time 1 3 5 7 Count 578 317 204 117 (a) Make a scatterplot of the data. Count 800 Time 700 600 500 400 300 200 100 LLLL Time 4 5 6 7 8 0 0 1 2 3 0 Count 0 100 200 300 400 500 600 700 800 Count Time 800 700 600 500 400 300 200 0 Count 0 100 200 300 400 500 600 700 800 1 2 3 4 IL Time 6 7 8 5 0

Answer 1

a) The correct scatter graph is C) as the points correspond to the right representation on the scatterplot

"Time" is an explanatory variable that's why it is on the x-axis in the scatterplot
Correct option A)

b) We can see that the relationship is curved and not linear
Correct option A)

c) We can see that there is only one data point corresponding to each time value. Also, from the scatterplot, we can see that the overall pattern is decreasing
Correct option: C)

2. a) Correlation is performed on two numerical variables. Here, occupation is a categorical variable and not on ratio scale. Hence, D) is correct

b) Correlation can't be equal to 1.14 as it varies from -1 to 1
Correct option: C)

c) In this case, neither variable is quantitative. Sex is a categorical variable as well as the color of cell phone.
Correct option: B)