The geometric distribution Quiz

1. $X\sim\mathrm{Geo}(0.25)$. Find $\mathrm{P}(X=3)$.

• A. $0.1406$
• B. $0.1875$
• C. $0.4219$
• D. $0.0469$

2. $X\sim\mathrm{Geo}(0.2)$. Find $\mathrm{P}(X>4)$.

• A. $0.5904$
• B. $0.8192$
• C. $0.4096$
• D. $0.4$

3. $X\sim\mathrm{Geo}(p)$ has mean $4$. What is its variance?

• A. $3$
• B. $4$
• C. $12$
• D. $16$

4. Which situation is best modelled by a geometric distribution?

• A. The number of heads in 10 tosses of a fair coin
• B. The number of tosses of a fair coin up to and including the first head
• C. The number of emails received in an hour
• D. The number of tails before the second head

5. $X\sim\mathrm{Geo}(0.1)$. What is the smallest $n$ with $\mathrm{P}(X\leq n)>0.9$?

• A. $20$
• B. $21$
• C. $22$
• D. $23$