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Lelu [443]
2 years ago
13

The electric cooperative needs to know the mean household usage of electricity by its non-commercial customers in kWh per day. T

hey would like the estimate to have a maximum error of 0.15 kWh. A previous study found that for an average family the standard deviation is 1.9 kWh and the mean is 16.7 kWh per day. If they are using a 98% level of confidence, how large of a sample is required to estimate the mean usage of electricity? Round your answer up to the next integer
Mathematics
1 answer:
Bogdan [553]2 years ago
7 0

Answer: 263

Step-by-step explanation:

As per given , we have

Population standard deviation : \sigma=1.9\text{ kWh}

maximum error : E=0.15 kWh

Significance level : \alpha=1-0.98=0.02

Critical value for 98% confidence interval : z_{\alpha/2}=1.28

Formula to find the sample size :

n=(\dfrac{z_{\alpha/2}\cdot \sigma}{E})^2\\\\=(\dfrac{1.28\times1.9}{0.15})^2\\\\=262.872177778\approx263

Hence, the minimum sample size required =263

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Sara has 20 sweets.
nalin [4]

Answer:

The probability that the two sweet will not be same type is \frac{111}{190}

Step-by-step explanation:

P(two sweets not same) = 1 - P( two sweets will be same)

There are 3 possible outcomes where two sweets will be same.

1. it can be two liquor-ice, 2. it can be 2 mint and 3. it can be two humbug

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Now we have:

P(two sweets not same) = 1 - P( two sweets will be same)

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2 years ago
n airline knows from experience that the distribution of the number of suitcases that get lost each week on a certain route is a
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Answer: 0.8313

Step-by-step explanation:

As per given we have,

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Also, the distribution of the number of suitcases that get lost each week on a certain route is approximately normal.

Since , z=\dfrac{x-\mu}{\sigma}

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P-value = P(10

=P(z

Hence, the probability that during a given week the airline will lose between 10 and 20 suitcases = 0.8313

8 0
2 years ago
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