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] ± ![t_{n-1;1-\alpha /2} * \frac{S}{\sqrt{20} }](https://tex.z-dn.net/?f=t_%7Bn-1%3B1-%5Calpha%20%2F2%7D%20%2A%20%5Cfrac%7BS%7D%7B%5Csqrt%7B20%7D%20%7D)
![t_{n-1;1-\alpha /2} = t_{19;0.975}= 2.093](https://tex.z-dn.net/?f=t_%7Bn-1%3B1-%5Calpha%20%2F2%7D%20%3D%20t_%7B19%3B0.975%7D%3D%202.093)
[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!
Plant
a simple subject is a person, place or thing
x+6 is x+6. It's an expression. Not sure what you need help with.
Answer:
y = 3x - 4
Step-by-step explanation:
The line crosses the y-axis at -4. The line goes 3 down and 1 left.
A variable next to any number means to multiply, so we would do the inverse operation -- We would divide 0.48 by 0.6, which is 0.8. Therefore, W=0.48. To check your work, multiply 0.6 by 0.8, and what do you know? It's 0.48! :)