Answer:
Step-by-step explanation:
Let's assign each person a variable using the first letter of his/her name.
Then we get the following equations based on the information given:
Then we can use substitution:
Rearrange the second equation:
Multiple the equation by 3:
Combine the equations to solve for a single variable (L):
Then we have a new equation:
Use substitution to get the rest:
Answer:
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.
Answer: - 0.71
Step-by-step explanation:
Let p = population proportion
po = sample proportion.
From the question,
p = 38% = 38/100 = 0.38
po = 32% = 32/100 = 0.32
Sample size (n) = 340.
Since our sample size is greater than 30 ( n= 340) we will be making use of a z test for our test statistics.
The population standard deviation of the data set is given below as
σ = √p(1 - p).
σ = √0.38 (1 - 0.38)
σ = √0.38 × 0.62
σ =√0.2356
σ = 0.49.
Z score = po - p/ (σ/√n)
Z score = 0.32 - 0.38/ (0.49/√340)
Z score = - 0.06 / 0.0266
Z score = - 0.71
The second option 0.04 is greater
