Answer:
c. (12.12, 18.48)
Step-by-step explanation:
Hello!
The study variable is X: number of times a racehorse is raced during its career.
The average number is X[bar]= 15.3 and the standard deviation is S= 6.8 obtained from a sample of n=20 horses.
To estimate the population mean you need that the variable has a normal distribution, in this case, we have no information about its distribution so I'll assume that it has a normal distribution. With n=20 the most accurate statistic to use for the estimation is a Students-t for one sample, the formula for the interval is:
X[bar] ± 

[15.3 ± 2.093 *
]
[12.12; 18.48]
Using a significance level of 95% you'd expect that the true average of times racehorses are raced during their career is included in the interval [12.12; 18.48].
I hope it helps!
I would say B. The mean is a good measure of central tendency.
I hope this helps!
Answer is 5.85 see picture
Hello from MrBillDoesMath!
Answer: 48.2 degrees
Discussion:
In the diagram, "6" is the x- distance along the side adjacent to theta, and
3 * sqrt(5) is the y-distance along the side opposite angle theta.
By definition of tangent of angle, using "@" for theta, we have
tan (@) = opposite/adjacent = 3 * sqrt(5) / 6 = sqrt(5)/2
So @ = (inverse tangent (sqrt(5)/2) ) = 48.189 degrees (approximately)
Thank you,
MrB