Answer:
B. z Subscript alpha divided by 2 zα/2 = 1.96.
Step-by-step explanation:
We are given that we want to construct a confidence interval. For this, the summary statistics for randomly selected weights of newborn girls:
n = 236, 
= 30.3 hg, s = 7.2 hg. The confidence level is 95%.
As we can clearly see here that the population standard deviation is unknown and the sample size is also very large.
It has been stated that when the population standard deviation is unknown, we should use t-distribution but since the sample size is very large so we can use z distribution also as it is stated that at very large samples; the t-distribution corresponds to the z-distribution.
Here, 
= level of significance = 1 - 0.95 = 0.05 or 5%
= 0.025 or 2.5%
So, the value of 
in the z table is given as 1.96 with a 2.5% level of significance.
10 runners ran fewer than 4 km
Let's call:
a = price of 1 apple
p = price of 1 peach
The total cost is the price of 1 apple times the number of apples plus the price of 1 peach times the number of peaches, therefore the system can be:
Solve for a in the second equation (you can choose to solve for any of the variables in any of the equations, try to understand what is the best):
a = (4.82 - 5p) / 4
Now, substitute in the first equation:
6 · (4.82 - 5p) / 4 + 9p = 7.86
7.23 - (15/2)p + 9p = 7.86
(3/2)p = 0.63
p = 0.42
Now, substitute this value in the formula found for a:
<span>a = (4.82 - 5·0.42) / 4</span>
= 0.68
Therefore, one apple costs
0.68$ and one peach costs
0.42$.
Answer:
12, 15, 24
Step-by-step explanation:
Let 1st # = x
Let 2nd # = x+3
Let 3rd # = 2x
Your equation is: x + (x+3) + 2x = 51
Add up all the x: x + x +3 +2x =51
Subtract 3 from both sides: 4x + 3 - 3 = 51 - 3
Divide 4 from both sides: 4x / 4 = 48 / 4
Your 1st number is x = 12
For the 2nd # it is 3 more than x so 12 + 3 = 15
For the 3rd # it is 2 times x so 2(12) = 24
Check your answers by adding up the numbers you solved: 12 + 15 +24 = 51
Does it equal to 51 as stated in the question? Yes, answers check out.
Answer:
4 * 4 ÷ 4 = 4
8 ÷ (2*2) = 2
Step-by-step explanation:
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I hope this helps.
