30 POINTS To study the effect of cell phone use on the time it takes to fall asleep, two experimental treatments are planned: one-hour cell phone use before bedtime for one group versus two-hour cell phone use for another. Which of the following groups would serve best as a control for this study?

A third group that uses a cell phone randomly for one hour or two hours before bedtime
A third group that uses a cell phone for 30 minutes before bedtime
A third group that uses a cell phone only if awoken in the middle of the night
A third group in which each subject chooses to use a cell phone for one hour or two hours before bedtime
A third group that does not use a cell phone before bedtime

A third group that does not use a cell phone before bedtime

Step-by-step explanation:

Both groups have the use of a cellphone before bedtime, and the amount used would affect their time to fall asleep, but another group is needed that doesn't use a cellphone to calculate the effect of it not being used and seeing the results.

option c) graph of line going through 1, 4 and 3, 10

step-by-step explanation:

let y equal to margo's coin collection

let x equal to number of years

at the begining x=0, y=1 → point=(x,y)→point=(0,1)

she adds 3 coins per year, then y=1+3x

at x=1, y=1+3(1)=1+3→y=4→point=(x,y)→point=(1,4)

at x=3, y=1+3(3)=1+9→y=10→point=(x,y)→point=(3,10)

the graph of line going through (1, 4) and (3, 10), then the option c is the correct.

a28=58

step-by-step explanation:

a1=a1+(n-1)d

a28= 4+ (28-1)2

a28=4+(27)(2)

a28=4+54

a28=58