Answer:
Sample mean from population A has probably more accurate estimate of its population mean than the sample mean from population B.
Step-by-step explanation:
To yield a more accurate estimate of the population mean, margin of error should be minimized.
margin of error (ME) of the mean can be calculated using the formula
ME=
where
- z is the corresponding statistic in the given confidence level(z-score or t-score)
- s is the standard deviation of the sample (or of the population if it is known)
for a given confidence level, and the same standard deviation, as the sample size increases, margin of error decreases.
Thus, random sample of 50 people from population A, has smaller margin of error than the sample of 20 people from population B.
Therefore, sample mean from population A has probably more accurate estimate of its population mean than the sample mean from population B.
Answer:
x = friends that paid discount price = 8
y = friends that paid regular price = 4
Step-by-step explanation:
Let
x = friends that paid discount price
y = friends that paid regular price
x + y = 12 (1)
6x + 8y = 80 (2)
From (1)
x = 12 - y
Substitute x = 12 - y into (2)
6x + 8y = 80 (2)
6(12 - y) + 8y = 80
72 - 6y + 8y = 80
- 6y + 8y = 80 - 72
2y = 8
y = 8/2
y = 4
Substitute y = 4 into (1)
x + y = 12 (1)
x + 4 = 12
x = 12 - 4
x = 8
x = friends that paid discount price = 8
y = friends that paid regular price = 4
You should write numbers in as many ways as you possibly can to make new connections in your brain. Knowing how to write numbers in many different ways can help you solve complex problems more easily. Doing this can also reinforce the mathematical principles and logic you have memorised.
Writing one in many different ways:
1=1/1=2/2=3/3=4/4=(-1)/(-1)=(-2)/(-2)
=1.0=1.00=1.000=(1/2)+(1/2)=(1/3)+(1/3)+(1/3)
=(1/4)+(1/4)+(1/4)+(1/4)
Writing a half in many different ways:
1/2=(1/4)+(1/4)=(1/6)+(1/6)+(1/6)
=(1/8)+(1/8)+(1/8)+(1/8)=4*(1/8)
=2/4=3/6=4/8=5/10=0.5=0.50
etc...etc...
93 is 60 percent from the original price.
The discount reduces the original price by 40 percent.
6.70-10.00=3.30
So you get $3.30 as change
