Answer:
a. Mean: 9.5.
Standard deviation: 2.18.
b. The critical value for signficantly low girl births is 5.14.
The critical value for signficantly high girl births is 13.86.
Step-by-step explanation:
a) If we take a sample of 19 births, all with individual probability of 0.5, we have a random binomial variable with n=19 and p=0.5.
This random variable will have mean and standard deviation calculated as:

b) Range rule of thumb: The standard deviation is approximately a quarter of the range, difference between the maximum and minimum value.
The range rule of thumb tells us that the expected minimum and maximum value are 2 standards deviation below or above, respectively, from the mean.
Then, the extreme expected values are:

The critical value for signficantly low girl births is 5.14.
The critical value for signficantly high girl births is 13.86.
D. 12 ÷ 4
since you're converting you have to divide
Answer:
-17
Step-by-step explanation:
f(t)=-2t^2+ 1
f(-3)=-2*-3^2+1
f(-3)=-2*9+1
f(-3)=-18+1
f(-3)=-17
solving proportions is simply a matter of stating the ratios as fractions, setting the two fractions equal to each other, cross-multiplying, and solving the resulting equation. You'll probably start out by just solving proportions, like this:
<span><span><span>Find the unknown value in the proportion: </span><span>2 : x = 3 : 9.</span></span><span>2<span> :</span> x = 3<span> :</span> 9</span>First, I convert the colon-based odds-notation ratios to fractional form:.Then I solve the proportion:<span>
</span><span>9(2) = </span><span>x(3)</span> <span>
1</span><span>8 = 3x</span><span>
</span><span>6 = x</span></span><span><span><span>Find the unknown value in the proportion: </span><span>(2x + 1) : 2 = (x + 2) : 5</span></span><span>(2x + 1)<span> :</span> 2 = (x + 2)<span> :</span> 5</span><span><span> ADVERTISEMENT</span><span> </span></span>First, I convert the colon-based odds-notation ratios to fractional form:Then I solve the proportion:<span>
</span><span>5(2x + 1) = 2(x + 2)</span><span>
</span><span>10x + 5 = 2x + 4</span><span>
</span><span>8x = –1</span><span>
</span><span>x = –1/<span>8</span></span></span>
The answer should be D) 22/25.