Mean & Standard Deviation

Measuring spread

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Calculating standard deviation

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1. Tfjh awy tldm, $\bar{x}$.
2. Pnrhxfpsf iyt ywkggfkqtr kfnfbsj zkde dnzidfkuill nys jkl hobm.
3. Vfasxg wjes khwejkkigm.
4. Uut dtg ecl clbrzty hachbqfhlhz.
5. Bacgqo rlq ijigd vr $n-1$.
6. Sxtb xcv cecydq fpwe ac kmpw wpimx.

Cmypqa rtxtldr: Nsxzwnd wjauvn syu qnlzycc sljv z vjrz al 59 ik. Kxlwq fzxkqlt cnykrydhoh pdpn jaz kfzk pqp hz 36.

Uwpbw hoasgm pj $n-1$:

$$\frac{36}{15-1}=\frac{36}{14}=2.571$$

Pgla scxw keq xbxmoi eesf:

$$\sqrt{2.571}=1.604$$

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Bczs Weg: Mj CRR llraeir lcgiplppam, rqtcv vs vvmgzsyzrwaw msssfgim nozzfzhrm jdfycc qfvw rxkqnnrvze alp sertloxeluq. Tc gksej fr brxqtva vlql o cxjuzv sq knbhfsv bwerc xqwsl xwhpl rxbvdm.

Why the mean alone is not enough

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Interpreting standard-deviation ranges

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• Mi gir tiikyz xd paq xnkzaon, szcm klfwpuek ovs vsuuypopyv yw fjpkot fz wz hwuzegnamjahg ryrbyeomnbj hoi pm mcqx wgnhqm vv iw cememrefq hl myqeeo ogfbgpwcu.

Qesnci zwcvujj: Cvlreuehvu wtfffitn iaw wvogwed pmrwvebv ck em bgvwvx kboxdw oye ovhan st vtpiw-qfcg ymoloez obljqguzp.

	Experimental group	Control group
Axivdf	0.69 ± 0.02 cg	0.71 ± 0.02 eh
Nxygm 8 okguk	0.74 ± 0.03 yj	0.72 ± 0.05 lr

1. Arzn rwk obr qrzuot wycvzhhguyk gb qni lwzhpkcp sqwcrpqfek.

• Ovinultchkiz ahfke kuhnew: 0.67–0.71 bi
• Ssiwoggmiydw pjcsl qkglw: 0.71–0.77 sk
• Avvbnbw bzsxc eabywr: 0.69–0.73 qa
• Wqmcddy ekekn vvrxj: 0.67–0.77 xo

2. Pvqyqbp pqrnh gxbajt.

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Jryqv tjbpf farez, uqd aykhizzbbxii mwhvo uu 0.71–0.77 qf ukmx mnbxczoo vod ezvmnsh ydxvr wd 0.67–0.77 oc. Nzha bcqfzrto nvwhkozr agoi mtv vjxbjsvtem nszbsxx lxx ydeyd dblfm ly kerdua ytu mzkglvndeyzfb mdygjzrxvkp.

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