Statistics - Proportions to make Inferences

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What is a proportion?

Back

A proportion is a mathematical equation that states that two ratios are equal. It is often used to compare parts of a whole.

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How do you calculate a proportion from a sample?

Back

To calculate a proportion from a sample, divide the number of favorable outcomes by the total number of outcomes in the sample.

Front

What is the purpose of using a sample in statistics?

Back

A sample is used in statistics to make inferences about a larger population without having to collect data from every individual in that population.

Front

If 12 out of 60 dogs are puppies, what is the proportion of puppies?

Back

The proportion of puppies is 12/60, which simplifies to 1/5 or 0.2.

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How can you estimate the number of puppies in a larger population using a sample?

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To estimate the number of puppies in a larger population, multiply the proportion of puppies in the sample by the total number of individuals in the population.

Front

What is the formula to estimate a population based on a sample?

Back

Estimated population = (Number of favorable outcomes in sample / Total outcomes in sample) x Total population.

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In a sample of 50 elk, if 8 are infected, what is the infection rate?

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The infection rate is 8/50, which simplifies to 0.16 or 16%.

Front

How do you apply the infection rate to estimate the number of infected elk in a population of 4,500?

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Multiply the infection rate (0.16) by the total population (4,500) to estimate the number of infected elk: 0.16 x 4,500 = 720 elk.

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What is a random sample?

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A random sample is a subset of individuals chosen from a larger population, where each individual has an equal chance of being selected.

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Why is it important to use random sampling in statistics?

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Random sampling helps to eliminate bias and ensures that the sample is representative of the population, leading to more accurate inferences.