The person with heart failure in which the heart fails to work properly due to increased blockage of the blood vessels has to weigh every day. The weight is measured every day as the increased or decreased weight signifies the condition of heart failure.
If the weight of the person is increased then it shows that the condition is getting worse.
To measure weight one must keep the record of weight by measuring the weight at the same time every day that is in the morning before the person goes to the bathroom or to urinate and before eating or drinking.
Since there are no options listed to choose from, my best guess would be watches, since a lot of apple watch products are now sold with built in heart monitors.
The median is usually preferred to other measures of central tendency when your data set is skewed (forms a skewed distribution) or you are dealing with ordinal data.
