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Find the area under the normal curve. Draw the illustration
z=1.03
A nationwide survey found out that the average time that college students spent on their personal computer is 10.5 hours per week. A random sample of 28 college students showed that they spent 8.5 hours per week using their computers with a standard deviation of 1.2 hours. Test whether the average number of hours spent by the 28 college students is significantly lower than the national average of 10.5 hours. Use a level of significance of 5%
The perimeter of a quarter circle is 7.14 kilometers. What is the quarter circle's radius?
(a) The mean and standard deviation of a set of values are 25 and 5, respectively. If a constant value 5 is added to each value, the coefficient of variation of the new set of values is equal to 10%.
(b) If (A) = 90, (AB) = 40, N = 150 and (β) = 80 then (αβ) = 30.
The numbers 3.2, 5.8, 7.9 and 4.5 have frequencies Y, (Y + 2), (Y - 3) and (Y + 6), respectively. If the arithmetic mean is 4.876, find the value of Y and write the whole series.
The value of Spearman's rank correlation coefficient of a set of non-repeating values was found to be 2/3. The sum of the squares of difference between the corresponding ranks was 55. Find the number of pairs.
Given the following data: r12 = 0' 8 , r13 = 0.6 and r23= 0.4 then find
(i) r12.3
(ii) r13.2
(iii) r23.1
(iv) R1.23
In a statistical study relating to the prices (in T) of two shares, X and Y, the following two regression lines were found as 8X - 10Y + 70 = 0 and 20X - 9Y - 65 = 0. The standard deviation of X = 3, then find (i) the values of X and Y, (ii) r(X, Y), and (iii) standard deviation of Y.
An investigation of 23713 households was made in an urban and rural mixed locality. Of these 1618 were farmers, 2015 well to do and 770 families were having at least one graduate. Of these graduate families 335 were those of farmers and 428 were well to do; also 587 well to do families were those of farmers and out of them only 156 were having at least one graduate. Obtain all the ultimate class frequencies.
If a finite population has four elements: 6, 1, 3, 2.
(a) How many different samples of size n = 2 can be selected from this population if you sample without replacement?
(b) List all possible samples of size n = 2.
(c) Compute the sample mean for each of the samples given in part b.
(d) Find the sampling distribution of x.
(e) Compute standard error.
(f) If all four population values are equally likely, calculate the value of the population mean μ . Do any of the samples listed in part (b) produce a value of x exactly equal to μ ?
