Answer:
864 miles
Step-by-step explanation:
648/9 = 72 mph
72 x 12 = 864
14 ÷ 1/2 × 3 (I hope it's right. I would have done this)
6.7x10^6 always the the decimal points go between the first 2 numbers, and you count the numbers of decimal places following it to get your scientific exponent
Answer:
Assuming ages are normally distributed, the 98% confidence interval for the population average age is [26.3, 35.7].
Step-by-step explanation:
We have to construct a 98% confidence interval for the mean.
The information we have is:
- Sample mean: 31
- Variance: 49
- Sample size: 15
- The age is normally distributed.
We know that the degrees of freedom are
![k=n-1=15-1=14](https://tex.z-dn.net/?f=k%3Dn-1%3D15-1%3D14)
Then, the t-value for a 98% CI is t=2.625 (according to the t-table).
The standard deviation can be estimated from the variance as:
![s=\sqrt {s^2}=\sqrt{49}=7](https://tex.z-dn.net/?f=s%3D%5Csqrt%20%7Bs%5E2%7D%3D%5Csqrt%7B49%7D%3D7)
The margin of error is:
![E=t_{14}*s/\sqrt{n}\\\\E=2.625*7/\sqrt{15}=18.375/3.873=4.7](https://tex.z-dn.net/?f=E%3Dt_%7B14%7D%2As%2F%5Csqrt%7Bn%7D%5C%5C%5C%5CE%3D2.625%2A7%2F%5Csqrt%7B15%7D%3D18.375%2F3.873%3D4.7)
Then, the CI can be constructed as:
![M-t*s/\sqrt{n}\leq\mu\leq M+t*s/\sqrt{n}\\\\31-4.7\leq \mu \leq 31+4.7\\\\26.3\leq \mu \leq 35.7](https://tex.z-dn.net/?f=M-t%2As%2F%5Csqrt%7Bn%7D%5Cleq%5Cmu%5Cleq%20M%2Bt%2As%2F%5Csqrt%7Bn%7D%5C%5C%5C%5C31-4.7%5Cleq%20%5Cmu%20%5Cleq%2031%2B4.7%5C%5C%5C%5C26.3%5Cleq%20%5Cmu%20%5Cleq%2035.7)