The quiz in a certain course has scores that are normally distributed with a mean of 76.8 with a standard deviation of 9.8.If 38 students are randomly selected, find the probability that the mean of their quiz scores is less than 80.

Round your answer4 places after the decimal point.

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The weights of the fish in a certain lake are normally distributed with a mean of 18 pounds and a standard deviation of 4 pounds.If 7 fish are randomly selected, find the probability that the mean weight is between 16.1 and 21 pounds.

Round your answer4 places after the decimal point.

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Use the normal distribution to approximate the desired probability.

Find the probability that in 236 tosses of a single 8-sided die, we will get at most 26 threes.

Round your answer to4 places after the decimal point.