Respuesta :
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:
[tex]\mu=n\cdot p=19\cdot0.5=9.5\\\\\sigma=\sqrt{np(1-p)}=\sqrt{19\cdot0.5\cdpot0.5}=\sqrt{4.75}=2.18[/tex]
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:
[tex]Min=\mu-2\sigma=9.5-2\cdot2.18=9.5-4.36=5.14\\\\Max=\mu+2\sigma=9.5+2\cdot2.18=9.5+4.36=13.86[/tex]
The critical value for signficantly low girl births is 5.14.
The critical value for signficantly high girl births is 13.86.
The likelihood of having a girl child is its probability
- The mean and the standard deviation are 9.5 and 2.18, respectively.
- The values separating the significantly low and high results are 5.14 and 13.86, respectively.
The given parameters are:
[tex]\mathbf{n = 19}[/tex] --- sample size
[tex]\mathbf{p = 0.5}[/tex] --- the probability of a girl child
(a) Mean and standard deviation
The mean is calculated as:
[tex]\mathbf{Mean = np}[/tex]
So, we have:
[tex]\mathbf{\bar x= 19 \times 0.5}[/tex]
[tex]\mathbf{\bar x = 9.5}[/tex]
The standard deviation is:
[tex]\mathbf{SD = \sqrt{np(1 - p)}}[/tex]
So, we have:
[tex]\mathbf{\sigma= \sqrt{19 \times 0.5 \times (1 - 0.5)}}[/tex]
[tex]\mathbf{\sigma= \sqrt{4.75}}[/tex]
[tex]\mathbf{\sigma= 2.18}[/tex]
Hence, the mean and the standard deviation are 9.5 and 2.18, respectively.
(b) The values separating the significantly low and high results
Using the range rule of thumb, we have:
[tex]\mathbf{Low = \bar x - 2\sigma}[/tex]
[tex]\mathbf{High = \bar x + 2\sigma}[/tex]
So, we have:
[tex]\mathbf{Low= 9.5 - 2 \times 2.18 = 5.14}[/tex]
[tex]\mathbf{High= 9.5 + 2 \times 2.18 = 13.86}[/tex]
Hence, the values separating the significantly low and high results are 5.14 and 13.86, respectively.
Read more about probabilities at:
https://brainly.com/question/11234923