Dear friends, Please read our latest blog post for an important announcement about the website. ❤, The Socratic Team

# How do I find the Z score for a statistic without standard deviation given Pop mean=.05%, n=100, Sample mean of .11%?

Then teach the underlying concepts
Don't copy without citing sources
preview
?

#### Explanation

Explain in detail...

#### Explanation:

I want someone to double check my answer

6
Dawn W. Share
Dec 7, 2016

I think the problem is really about a proportion so you do not need the standard deviation to find the standardized test statistic z. See the Explanation for the formula.

#### Explanation:

In your question, the sample proportion (p-hat) is 0.11%. The population proportion, p, is 0.05%. Use the following procedure:

Then teach the underlying concepts
Don't copy without citing sources
preview
?

#### Explanation

Explain in detail...

#### Explanation:

I want someone to double check my answer

2
Jun 6, 2015

By definition, Z score is:
$z = \frac{x - \mu}{\sigma}$
where $x$ is your datum, $\mu$ is the mean of your population and $\sigma$ is its standard deviation. Basically, it's a measure of deviation from the mean in units of standard deviation.

Unless I misunderstood your problem, I see no way you can calculate this number without knowing a standard deviation.

• 41 minutes ago
• 42 minutes ago
• 45 minutes ago
• 45 minutes ago
• A minute ago
• 5 minutes ago
• 14 minutes ago
• 34 minutes ago
• 35 minutes ago
• 38 minutes ago
• 41 minutes ago
• 42 minutes ago
• 45 minutes ago
• 45 minutes ago
• Bio
• Pre
• Org
• Tri
• Ear
• Alg
• Che
• Ana
• Env
• Psy
• Cal
• Soc
• U.S
• Wor
• Phy
• Sta
• Ast
• Ast
• Eng
• Geo
• Pre