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pshichka [43]
2 years ago
6

In a study of 225 adults, the mean heart rate was 72 beats per minute. Assume the population of heart rates is known to be appro

ximately normal with a standard deviation of 10 beats per minute. What is the 90% confidence interval for the mean beats per minute?
Mathematics
2 answers:
Aleonysh [2.5K]2 years ago
3 0
<span> The lower and upper bounds of the confidence intervals must be equally distanced from the mean 
so it will be
</span><span>70.9 - 73.1 
</span>hope it helps
bonufazy [111]2 years ago
3 0

Answer:

Confidence interval lower bound = 72-1.097 = 70.903

                                Upper bound = 72+1.097=73.097

Step-by-step explanation:

In a study of 225 adults, the mean heart rate was 72 beats per minute

Hence sample size n = 225

sigma = population std deviation = 10

Sample std deviation = 10/sqrt 225 = 0.67

Since n is sufficiently large we can use Z critical value for finding confidence interval 90%

Two tailed z critical for 90% is 1.645

Margin of error = 1.645 *0.67=1.097

Confidence interval lower bound = 72-1.097 = 70.903

                                Upper bound = 72+1.097=73.097

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Colt1911 [192]
Let, Price of a shirt = x
Price of a Jeans = y

Equations would be: 4x + 3y = 150
x + 2y = 70
x = 70-2y

Substitute it into first equation, 
4(70-2y) + 3y = 150
280 - 8y + 3y = 150
-5y = -130
y = 130/5
y = 26

Substitute it into 2nd equation, 
x + 2(26) = 70
x = 70-52
x = 18

So, Cost of a Shirt = $18  &  Cost of a Jeans = $26

Hope this helps!
3 0
2 years ago
Write a comparison sentence to represent this equation 6x7=42
Setler [38]
42 / 7 = 6
bc it is the complete opposite
8 0
3 years ago
Read 2 more answers
MATH HELP!!!
AfilCa [17]
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multiply that by number of years until he retires:

761280 / 29280 = 26 years

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4 0
3 years ago
Read 2 more answers
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yaroslaw [1]

Answer:

See Below.

Step-by-step explanation:

We are given that ∠1 and ∠7 are supplementary.

And we would like to prove that a is parallel to b.

  Statements:                                           Reasons:

\textbf{\textsf{1. $\angle 1$ and $\angle 7$ are supplementary}}              Given

\textsf{2. $m\angle3$ + $m\angle 7$ $= 180$}                               Supplementary Angles

\textsf{3. $\angle3$ and $\angle7$ are supplementary}                Definition of Supplementary

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3 0
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A paintball court charges an initial entrance fee plus a fixed price per ball.
m_a_m_a [10]

Answer : The cost of 10 balls will be, 13.5 dollars

Step-by-step explanation :

As we are given the following expression:

P=0.80\times n+5.50

where,

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n = number of balls used

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Thus, the cost of 10 balls will be, 13.5 dollars

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3 years ago
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