Answer:
Step-by-step explanation:
We want to determine a 90% confidence interval for the true population mean textbook weight.
Number of sample, n = 22
Mean, u = 64 ounces
Standard deviation, s = 5.1 ounces
For a confidence level of 90%, the corresponding z value is 1.645. This is determined from the normal distribution table.
We will apply the formula
Confidence interval
= mean ± z ×standard deviation/√n
It becomes
64 ± 1.645 × 5.1/√22
= 64 ± 1.645 × 1.087
= 64 ± 1.788
The lower end of the confidence interval is 64 - 1.788 = 62.21 ounces
The upper end of the confidence interval is 64 + 1.788 = 65.79 ounces
Therefore, with 90% confidence interval, the true population mean textbook weight is between 62.21 ounces and 65.79 ounces
Answer:
x is the price of the meal
(1+0.0825 + 0.18) is the total percentage on top of the price he pays with sales tax and tip.
Step-by-step explanation:
The factor x is the price of the meal. The factor (1 + 0.0825 + 0.18) is the 100% of the price, the sales tax on that price and the tip on the total. 1 + 0.0825 + 0.18 = 1.2625 is the total percentage he pays on the price. He pays 26.25% in addition of the price of the meal to cover tax and tip.
First computer takes x min. For 1 min it does 1/x part of work.
Second computer takes (x+24) min. For one min it does 1/(x+24) part of work.
Both computers for one min do (1/x+1/(x+24)) part of work.
At the same time, both computers for one min do 1/9 part of work.
The ratio indicates that there are 8 dolls for every 7 teddy bears. That means that if there is 16 dolls, then there is 14 teddy bears. And that if there is 24 dolls, then there is 21 teddy bears. You could continue this pattern, or you could divide and multiply. If you have 160 dolls, then do 160/8 to simplify the ratio. You get 20. So if there is (8x20) dolls, then there is (7x20) teddy bears. 7x20 is 140, so there are 140 teddy bears.