Q.2.105 - Elementary Statistics

Question

Parkinson's Disease. Parkinson's disease affects internally generated movements such as movements recalled from memory. L-Dopa is a drug that is used in clinical treatment of Parkinson's disease. In the article, "L-Dopa Induces Under-Damped Visually Guided Motor Responses in Parkinson's Disease" (Experimental Brain Research, Vol. 202, Issue 3, pp. 553-559), Wing-Lok Au et al. explore the effects of L-Dopa on patients with Parkinson's disease. Following is a stem-and-leaf diagram of the ages, in years, at which a sample of $14$ patients experienced the onset of symptoms of Parkinson's disease.

How many of these $14$ patients were

a. under $45$ years old at the onset of symptoms?

b. at least $65$ years old at the onset of symptoms?

c. between $50$ years old and $64$years old, inclusive, at the onset of symptoms?

Step-by-Step Solution

Answer

a). The number of patients is $1$.

b). The number of patients is  $3$.

c). The number of patients is  $8$.

Part (a) Step 1: Given Information

The data is given as,

Part (a) Step 2: Explanation

The number of patients under $45$ years old under symptoms is the sum of lines starting with $3$ or $4$ so,

$1+0=1$

Part (b) Step 1: Given Information

The data is given as,

Part (b) Step 2: Explanation

The number of patients at least $65$ years old under symptoms is the sum of lines starting with $6$ or $7$ so,

$1+2=3$.

Part (c) Step 1: Given Information

The data is given as,

Part (c) Step 2: Explanation

The number of patient between $50$ and $64$ years old under symptoms is the sum of lines starting with $5$ or $6$ so,

$7+0+1=8$.