Can vaccination be regarded as a preventive measure for smallpox from the given data:
(i) Of 1482 persons in a locality exposed to smallpox, 368 in all were attacked, and
(ii) Of 1482 persons, 343 had been vaccinated and of these only 35 were attacked.
Thus, we find that ___ __________ ____ __________ _________ _______ _________ _____ ______ _____ ___ ___.
____ ______ _____ _______ _____ _________ ________.
________ ____ _______ ____ ___.
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The following is the distribution of age (in years) of 800 workers:
| Age Group | Age Group |
| 20 — 25 | 50 |
| 25 — 30 | 70 |
| 30 — 35 | 100 |
| 35 — 40 | 180 |
| 40 — 45 | 150 |
| 45 — 50 | 120 |
| 50 — 55 | 70 |
| 55 — 60 | 60 |
Suppose X and Y are the two variables having the correlation coefficient 0.85. The following are the values they have:
| X | Y |
| 10 | 40 |
| 30 | 30 |
| 50 | 70 |
| 60 | 80 |
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.
If X1, X2, X3, ..., Xn and Y1, Y2, Y3, ..., Yn are the variate values of two variables X and Y, and their geometric means are G1and G2, respectively, then geometric mean of (xj/yi); i = 1, 2, ... n will be (G1/G2).
If X and Y are two independent variables and the variables U = X+ Y and V= X –Y, then the
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.
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