Answer
See below.
Work Step by Step
The mean of $n$ numbers is the sum of the numbers divided by $n$. The median of $n$ is the middle number of the numbers when they are in order (and the mean of the middle $2$ numbers if $n$ is even). The mode of $n$ numbers is the number or numbers that appear(s) most frequently. Hence here the mean: $\frac{19+23+23+26+30+31+34}{7}\approx26.571$, the median is the middle in the sequence $19, 23, 23, 26, 30, 31, 34$, which is: $26$, the mode is $23$. The range is the difference between the largest and the smallest data value. The standard deviation of $x_1,x_2,...,x_n$ is (where $\overline{x}$ is the mean of the data values): $\sqrt{\frac{(x_1-\overline{x})^2+(x_2-\overline{x})^2+...+(x_n-\overline{x})^2}{n}}$. Hence here the range is: $34-19=15$ and the standard deviation is: $\sqrt{\frac{(19-26.571)^2+(23-26.571)^2+...+(34-26.571)^2}{7}}\approx4.9239$
When every value of a data set is multiplied by a constant, the new mean, median, mode, range, and standard deviation can be obtained by multiplying each original value by the constant. Here the constant is $3$, hence the mean: $26.571\cdot 3=79.713$, the median: $26\cdot 3=78$, the mode:$23\cdot 3=69$, the range:$15\cdot 3=45$, and the standard deviation: $4.9239\cdot 3=14.7717$.
