(6ƒ² − 9ƒ + 10) − (− 2ƒ² − ƒ+3)
2 answers:
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Answer:
D
Step-by-step explanation:
Given the quadratic
d = - 16t² + 12t ← subtract d from both sides
- 16t² + 12t - d = 0 ← in standard form
with a = - 16, b = 12, c = - d
Use the quadratic formula to solve for t
t = ( - 12 ± ) / - 32
= ( - 12 ± ) / - 32
= ( - 12 ± ) / - 32
= ( - 12 ± 4) / - 32
= ±
= ±
= ±
→ D
Answer: 208.
Step-by-step explanation:
The formula to find the minimum sample size is given by :-
(1)
, where z* = critical z-value (two tailed).
= Standard deviation ( from prior study ) and E = Margin of error.
As per given , we have
Margin of error : E= 0.29
Confidence level = 85%
Significance level =
Using z-table , the critical value (two -tailed)=
As per previous study , Variance =
Now, the required minimum sample size = [Substitute the values in formula (1)]
[ Round to the next integer]
Hence, the minimum number of third graders that must be included in a sample = 208.