Weakly earnings on a certain import venture are approximately normally distributed with a known mean of $410 and unknown standard deviation. If the proportion of earnings over $430 is 31%, find the standard deviation. Answer only up to two digits after decimal.
Weakly earnings on a certain import venture are approximately normally distributed with a known mean of...
Weakly earnings on a certain import venture are approximately normally distributed with a known mean of $386 and unknown standard deviation. If the proportion of earnings over $419 is 25%, find the standard deviation. Answer only up to two digits after decimal.
1) The household income in a certain community is normally distributed with a mean of $42,000 and a standard deviation of $5,000. The proportion of households with incomes of at least $50000 is between: a) 5% and 6% b) 44% and 45% c) 94% and 95% d) none 2) The actual weight of "8 oz. chocolate bar" produced by a certain machine are normally distributed with mean 8.1 oz. and standard deviation of 0.1 oz. only 5% of the bars...
The lifetime of a certain brand of tires is approximately normally distributed, with a mean of 45,000 miles and a standard deviation of 2,500 miles. The tires carry a warranty for 40,000 miles.(Show work please) What proportion of the tires will fail before the warranty period? What proportion of the tires will fail after the warranty expires, but before they have lasted for 41,000 miles? Suppose a sample of 100 randomly selected tires are tested, what is the probability that...
The daily sales of a certain variety store are approximately normally distributed with a mean of $10000 and a standard deviation of $2000. What is the probability that a random sample of 100 days will yield a mean greater than $9800?
It is known that the height (X) of females in a certain country is normally distributed with mean μ = 1600 millimeters (mms) and standard deviation σ = 63 mms. Use the normal distribution to calculate the proportion of females who are at least 1553 and at most 1621 millimeters tall, i.e. P( 1553 < X < 1621 ) Answer to four decimal place.
Suppose the lengths of the pregnancies of a certain animal are approximately normally distributed with mean u = 282 days and standard deviation o = 20 days. Complete parts (a) through (f) below. (a) What is the probability that a randomly selected pregnancy lasts less than 274 days? The probability that a randomly selected pregnancy lasts less than 274 days is approximately (Round to four decimal places as needed.)
Suppose the lengths of the pregnancies of a certain animal are approximately normally distributed with mean equals 137 days and standard deviation equals 12 days. The probability that a random sample of size 17 will have a mean gestation period within 12 days of the mean is ? .
The annual assets for First Michigan corporation is approximately normally distributed with standard deviation 58 million. The mean is not known. However it is known that 58% of the assets is over 210.3 million. Find the mean assets value in millions. Answer to 2 decimal places.
The annual assets for First Michigan corporation is approximately normally distributed with standard deviation 44 million. The mean is not known. However it is known that 58% of the assets is over 210.1 million. Find the mean assets value in millions. Answer to 2 decimal places.
The annual assets for First Michigan corporation is approximately normally distributed with standard deviation 20 million. The mean is not known. However it is known that 57% of the assets is over 217.5 million. Find the mean assets value in millions. Answer to 2 decimal places.