Answer:
C. Different sample proportions would result each time, but for either sample size, they would be centered (have their mean) at the true population proportion.
Step-by-step explanation:
From the given information;
A political polling agency wants to take a random sample of registered voters and ask whether or not they will vote for a certain candidate.
A random sample is usually an outcome of any experiment that cannot be predicted before the result.
SO;
One plan is to select 400 voters, another plan is to select 1,600 voters
If the study were conducted repeatedly (selecting different samples of people each time);
Different sample proportions would result each time, but for either sample size, they would be centered (have their mean) at the true population proportion. This is because a sample proportion deals with random experiments that cannot be predicted in advance and they are quite known to be centered about the population proportion.
Start with how much profit they are making off each race entry. People pay $55 to race, but $15 of that is expenses so they are only profiting $40 for each entry. Now write one side of the equality. They start with $10,000 in donations, and then have a $40 profit for each race entry. So 10,000+40x. X will represent the unknown number of race entries. What do we want that expression to be equal to? We want 10000+40x>55000. It can also be greater than or equal to, not just greater than.
Solve for x. Subtract 10000 from each side resulting in 40x>45000. Divide each side by 40 to solve for x. X>1125. X needs to bbe greater than or equal to 1125. If there are 1125 race entries, the charity will profit exactly $55000, so the lowest number of race entries is 1125
<span> 0.81x - 0.45 is subtracted from 3.28x + 1.4
</span>3.28x + 1.4 - (0.81x - 0.45) = 3.28x + 14 - 0.81x + 0.45
= (3.28x - 0.81x) + ( 14 +0.45)
= 4.09x + 14.45
Step-by-step explanation:
27.7%
Step-by-step explanation:
Let's call:
n: the number of adults interviewed
t: number of adults who watch tennis
d: number of adults who practice some sport
x: number of adults who watch tennis and do not practice a sport
The probability that a randomly chosen adult watches tennis and does not play any sports is calculated as follows:
- We calculate the probability that a selected adult will see tennis.
P(t) = 92/140 = 0.657
- We calculate the probability that an adult plays a sport:
P(d) = 81/140 = 0.5786
- We calculate the probability that an adult will see tennis and play some sport (See diagram attached)
P (t ∩ d) = 0.657 (0.5786) = 0.3802
Finally the probability that an adult who sees tennis does not play any sport is:
P(x) = P(t) - P(t ∩ d) = 0.657 - 0.3802
P(x) = 0.277
