If we think about a normal curve / bell curve and the 68-95-99.7 rule, we know that the majority of data will lie within 1, 2, or 3 standard deviations from the mean. The mean is in the center of the curve, and to each side of the mean, 34% of the data lies 1 standard deviation on either side of the mean. Therefore, we need to add and subtract one standard deviation from the mean.
85 + 12 = 97
85 - 12 = 73
Correct Answer: B. 73 - 97
Hope this helps!! :)
Answer:
91.2
Step-by-step explanation:
add to both sides 15.2 so 76+15.2=91.2
Answer: 547
Step-by-step explanation: The margin of error formulae is given below as
Margin of error = critical value ×(σ/√n)
Where σ = standard deviation and n is the sample size.
From our question, margin of error = 0.08
Variance is 1.691,
hence σ = √variance = √1.691
= 1.3.
We will be using a z test for our critical value this is because a soft drink manufacturer will always produce drinks more than 30 in numbers.
The critical value for a 85% confidence interval is 1.44.
Hence critical value is 1.44.
By substituting the parameters, we have that
0.08 = 1.44 × 1.3/ √n
0.08 = 1.873/ √n
By cross multiplying
0.08 × √n = 1.873
√n = 1.873/ 0.08
√n = 23.41
n = (23.41)²
n = 547.
80=6th graders
40=5th graders
80+40=120
120/22= 60/11
120/25=24/5
120/30= 4
There are 30 students in each class because he teaches 4 class and 120/30 will give you 4.
