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ehidna [41]
3 years ago
12

To calculate the area of a circle, use the formula A = Π r2. True False

Mathematics
2 answers:
dimaraw [331]3 years ago
8 0
True :) .............
saw5 [17]3 years ago
6 0
It's True (Trust me)
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g In a certain rural county, a public health researcher spoke with 111 residents 65-years or older, and 28 of them had obtained
Marat540 [252]

Answer:

95% confidence interval for the percent of the 65-plus population that were getting the flu shot is [0.169 , 0.331].

Step-by-step explanation:

We are given that in a certain rural county, a public health researcher spoke with 111 residents 65-years or older, and 28 of them had obtained a flu shot.

Firstly, the Pivotal quantity for 95% confidence interval for the population proportion is given by;

                          P.Q. =  \frac{\hat p-p}{\sqrt{\frac{\hat p(1-\hat p)}{n} } }  ~ N(0,1)

where, \hat p = sample proportion of residents 65-years or older who had obtained a flu shot = \frac{28}{111} = 0.25

          n = sample of residents 65-years or older = 111

          p = population proportion of residents who were getting the flu shot

<em>Here for constructing 95% confidence interval we have used One-sample z test for proportions.</em>

<u>So, 95% confidence interval for the population proportion, p is ;</u>

P(-1.96 < N(0,1) < 1.96) = 0.95  {As the critical value of z at 2.5% level

                                                of significance are -1.96 & 1.96}  

P(-1.96 < \frac{\hat p-p}{\sqrt{\frac{\hat p(1-\hat p)}{n} } } < 1.96) = 0.95

P( -1.96 \times {\sqrt{\frac{\hat p(1-\hat p)}{n} } } < {\hat p-p} < 1.96 \times {\sqrt{\frac{\hat p(1-\hat p)}{n} } } ) = 0.95

P( \hat p-1.96 \times {\sqrt{\frac{\hat p(1-\hat p)}{n} } } < p < \hat p+1.96 \times {\sqrt{\frac{\hat p(1-\hat p)}{n} } } ) = 0.95

<u>95% confidence interval for p</u> = [ \hat p-1.96 \times {\sqrt{\frac{\hat p(1-\hat p)}{n} } },\hat p+1.96 \times {\sqrt{\frac{\hat p(1-\hat p)}{n} } } ]

   = [ 0.25-1.96 \times {\sqrt{\frac{0.25(1-0.25)}{111} } } , 0.25+1.96 \times {\sqrt{\frac{0.25(1-0.25)}{111} } } ]

   = [0.169 , 0.331]

Therefore, 95% confidence interval for the percent of the 65-plus population that were getting the flu shot is [0.169 , 0.331].

7 0
3 years ago
Explain the difference between accuracy and precision
nata0808 [166]

Precision is more like consistency. Take a rifle range for example. Sure, all the shots may be off centered, but if they're tightly grouped together, it shows that the shooter had precision in their shooting. Accuracy is how close to spot on the attempts or shots generally are. They would end up more towards the center, but a little more spread out.

3 0
3 years ago
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Two mechanics worked on a car. The first mechanic worked for
ivann1987 [24]
20x + 15y = 2000
x + y = 115
55+60=115

20 (55) + 15 (60)=2000
1100+900=2000
2000=2000
5 0
2 years ago
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Express the ratio in its simpilest form<br><br> 4:2:2
kotykmax [81]
The ratio in simplest form would be 1:2:2.
5 0
2 years ago
The sum of two numbers is 85. twice one number plus four times the other is 218. find the numbers
Nina [5.8K]
X + y = 85
2x + 4y = 218
x = 85 - y 
<span>2(85 - y) + 4y = 218 </span>
<span>170 - 2y + 4y = 218 </span>
<span>170 + 2y = 218 </span>
<span>2y = 48 </span>
<span>y = 24 </span>
<span>x = 61</span>
6 0
3 years ago
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