Probability

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There is no simple answer to the question because the children's genders are not independent events. They depend on the parents' ages and their genes.
If you believe that the children's genders are not independent then you would need to get empirical evidence from all families with four or more children in which the first three children were girls. If there are g families in which the fourth is a girl and b where the fourth is a boy then the required probability is b/(g+b).

However, if you assume that the children's genders are independent events then, given that the probability of a boy is approx 0.52, the probability of the fourth child is a boy is 0.52

"Playing cards" are chosen at random.

For which measure of central tendency will the sum of the deviations always be zero?

Whether or not the student passes depends on the level of the examinations, the effort put in by the student, the quality of his teachers. There are too many contributory factors for a simple answer.

In 1,307,674,368,000, or 15! ways.

A discrete random variable is a variable that can only take some selected values. The values that it can take may be infinite in number (eg the counting numbers), but unlike a continuous random variable, it cannot take any value in between valid results.

Standard deviations are measures of data distributions. Therefore, a single number cannot have meaningful standard deviation.

Two.

The probability of each coin flip, independently, is 0.5 or 50%. The probability of getting one result (either heads or tails) four times in a row is 0.5 to the fourth power or 0.0625, which equals 6.25%

It is 3/1024 = 0.00293, approx.

There is insufficient information in the question to properly answer it. You did not provide the list of "the following". Please restate the question.

However, by definition of probability, a probability less than 0 (the event will never happen) or greater than 1 (the event will always happen) is impossible, so maybe that answers your question.

1

Since there are only two options for the answer, on average the student will answer half of the answers correctly.

(X-61)/10.2=.878

X = 69.95

approximately 70

Karl Pearson simplified the topic of skewness and gave us some formulas to help.

The first is the Pearson mode or first skewness coefficient. It is defined by the (mean-median)/standard deviation. So in this case the Pearson mode is:

(8-6)/2

=1

There is also the Pearson Median. This is also called second skewness coefficient. It is defined as 3(mean-median)/standard deviation which in this case is

6/2

=3

hence the distribution is positive skewed

The classic example is a Bell curve. IQ testing (using the WAIS, or Wechsler Adult Intelligence Scale) yields a peak at the 100-105 IQ mark, with a downward curve on either side of the peak - representing the higher and lower IQ scores, respectively.

1 in 15 chances that the marble will be blue, because there are 15 marbles all together in a bag, and you are only picking one out of it.

Z = -0.8416

The probability of that event, some time during your lifetime, is pretty close to 1.

A disadvantage to a large sample size can skew the numbers. It is better to have sample sizes that are appropriate based on the data.

The probability that she gets exactly 3 right is 8C3*(1/3)3*(2/3)5 = 0.2731 approx.

If you assume that a grocery bill is normally distributed then the lowest spend by the top 25% is 67.46.

It is a symmetrical, "bell-shaped" curve. The tails are infinitely long.