What is random sampling

Mathematics

2 answers:

jasenka [17]4 years ago

7 0

Is a subset of individuals chosen from a larger set.

Katyanochek1 [597]4 years ago

7 0

Is a subset of statistical population which each member of the subset has an equal probability of being chosen

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Is 8 cm larger than 3/8 inch

Hoochie [10]

Nope. 3/8 an inch is 0.9525 cm.

7 0

3 years ago

locksmith larry charges $90 for a house cal plus $20 per hour. Locksmith Barry charges $50 for a house call plus $30 per house.

nadya68 [22]

Answer:

4 hours

Step-by-step explanation:

Equations :

Larry : y = 20x + 90

Barry : y = 30x + 50

Equate both to find the number of hours at which they both charge the same :

20x + 90 = 30x + 50
30x - 20x = 90 - 50
10x = 40
x = 4 hours

4 0

3 years ago

A teacher was interested in knowing the amount of physical activity that his students were engaged in daily. He randomly sampled

klasskru [66]

Answer:

The standard error of the mean is 4.5.

Step-by-step explanation:

As we don't know the standard deviation of the population, we can estimate the standard error of the mean from the standard deviation of the sample as:

$\sigma_{\bar{x}}\approx\frac{s}{\sqrt{n}}$

The sample is [30mins, 40 mins, 60 mins, 80 mins, 20 mins, 85 mins]. The size of the sample is n=6.

The mean of the sample is:

$\bar{x}=\frac{1}n} \sum x_i =\frac{30+40+60+80+20+85}{6}=52.5$

The standard deviation of the sample is calculated as:

$s=\sqrt{\frac{1}{n-1}\sum (x_i-\bar x)^2} \\\\ s=\sqrt{\frac{1}{5}\cdot ((30-52.5)^2+(40-52.5)^2+(60-52.5)^2+(80-52.5)^2+(20-52.5)^2+(85-52.5)^2}\\\\s=\sqrt{\frac{1}{5} *3587.5}=\sqrt{717.5}=26.8$