Suppose we construct a histogram of the marks obtained by students. When the quiz is very difficult, the shape of the histogram will be Ou shaped Uniform Right skewed (positive skewed) Symmetric O Left skewed (negative skewed) Out of complete list of 241,472,385 adults in the United States, 15,000 adults are selected using the voters registration list. What type of sampling is this? Convenience Sampling Stratified Random Sampling Cluster Sampling Systematic Sampling O Simple Random Sampling Find IQR (InterQuartile Range) from the data 51, 50, 3, 7, 1, 20, 18, 10, 15 O 20 35 25 O 15 5: O 30