A light bulb consumes
1 answer:
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Answer:
Kristen bought 2 fancy shirts and 5 plain t-shirts.
Step-by-step explanation:
Given that,
Kristen spent $131 on 7 shirts.
Cost of one fancy shirt = $28
Cost of one plain t-shirt = $15
Let,
x be the number of fancy shirts
y be the number of plain t-shirts
x+y = 7 Eqn 1
28x+15y=131 Eqn 2
Multiplying Eqn 1 by 15
15(x+y=7)
15x+15y=105 Eqn 3
Subtracting Eqn 3 from Eqn 2
(28x+15y)-(15x+15y)=131-105
28x+15y-15x+15y=26
13x=26
Dividing both sides by 13
Putting x=2 in Eqn 1
2+y=7
y=7-2
y=5
Hence,
Kristen bought 2 fancy shirts and 5 plain t-shirts.
The 90% , 99% confidence interval for the population mean is 32.145 < < 35.855 and 31.093 <
< 36.907
Probability is the study of likeliness of an event to happen.
It is given that
Total Population = 50
Mean = 35
The confidence interval is given by
is the mean
z is the confidence level value
s is the standard deviation
n is the population width
(a) The 90% confidence interval for the population mean
90% = 0.05
Z = 1.64
34 1.64 * 8 / √50
34 1.855
32.145 < < 35.855
(b) The 99% confidence interval for the population mean
99% = 0.005
Z=2.57
34 2.57 * 8 / √50
34 2.907
31.093 < < 36.907
Therefore the confidence interval for population mean has been determined.
The complete question is
A simple random sample of 50 items from a population width =7 resulted in a sample mean of 35. If required, round your answers to two decimal places.
a. Provide a 90% confidence interval for the population mean
b. Provide a 99% confidence interval for the population mean
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